GIFT  OF 


ELEMENTS 

OF 

FUEL  OIL  AND  STEAM  ENGINEERING 


THE   1918  TECHNICAL  SERIES 

Elements  of  Western  Water  Law  (revised) 

By  A.  E.  Chandler $2.50 

Elements  of  Fuel  Oil  and  Steam  Engineering 

By  Robert  Sibley  and  Chas.  H.  Delany $3.00 

Public   Utility   Rates 

By  C.  E.  Grunsky (Announcement  later) 

TECHNICAL  PUBLISHING  COMPANY 
Crossley  Building,  San  Francisco 


Elements 
of 

Fuel  Oil  and  Steam  Engineering 

A  PRACTICAL  TREATISE  DEALING 
WITH  FUEL  OIL,  FOR  THE  CENTRAL 
STATION  MAN,  THE  POWER  PLANT 
OPERATOR,  THE  MECHANICAL  EN- 
GINEER AND  THE  STUDENT 

BY 
ROBERT  SIBLEY,  B.  S. 

Editor   Journal    of   Electricity;    formerly   Professor    of    Mechanical 
Engineering,    University    of    California;    Fellow    American 
Institute  of  Electrical  Engineers;  Member  American 
Society  of  Mechanical  Engineers,   and  Past- 
president  of  the  San  Francisco  Section. 

AND 

CHAS.  H.  DELANY,  B.  S.,  M.  M.  E. 

Steam   Power  Plant   Specialist,    Pacific    Gas    &   Electric   Company; 

Lecturer    on    Steam    Engineering,     Extension    Division 

University  of  California;  Member  American 

Society  of  Mechanical  Engineers. 

First  Edition 

San  Francisco: 

Technical  Publishing  Company 
London:  E.  &  F.  N.  Spon,  Limited 

1918 


-\  Y    * 


Copyright,  1918,  by  the 
Technical  Publishing  Company 


PREFACE 

Fuel  oil  in  its  power  generating  characteristics  is 
a  factor  of  prime  importance  on  land  and  sea  in  these 
momentous  times. 

The  clarion  call  to  service  is  heard  on  all  sides. 
And  in  answering  this  call,  it  must  be  remembered 
that  to  save  is  to  serve. 

Implicitly  hoping  that  this  book  may  aid  in  es- 
tablishing a  fuller  knowledge  of  the  fundamental  laws 
of  fuel  oil  and  steam  engineering,  and  that  a  conse- 
quent saving  in  fuel  will  inevitably  result  where  these 
laws  are  properly  put  into  practice,  no  matter  how 
small  may  be  the  resulting  good,  the  authors  offer  to 
the  engineering  'and  industrial  world  at  this  time  this 
work,  which  had  its  incipiency  six  years  ago  in  cer- 
tain power  economy  tests  in  Oakland,  California,  later 
to  be  used  in  lecture  notes  at  the  University  of  Califor- 
nia, and  finally  to  be  rounded  out  by  a  study  of  power 
plant  practice  in  California  covering  a  period  of  several 
years. 

The  book  has  as  its  underlying  theme  a  study  of 
fuel  oil  power  plant  operation,  and  the  use  of  evapora- 
tive tests  in  increasing  the  efficiency  of  oil' fired  plants. 
To  accomplish  this  end  the  subject  matter  has  been 
treated  in  three  main  subdivisions :  First,  an  exposi- 
tion of  the  elementary  laws  of  steam  engineering ;  sec- 
ond, the  processes  involved  in  the  utilization  of  fuel 
oil  in  the  modern  power  plant ;  and,  third,  the  testing 
of  boilers  when  oil  fired. 

In  treating  the  first  subdivision,  the  elementary 
laws  of  steam  engineering  are  set  forth  in  a  new  man- 
ner, in  that  the  viewpoint  is  taken  from  that  of  the 
oil-fired  instead  of  the  coal-fired  power  plant  operator. 
In  the  second  subdivision,  the  results  of  considerable 
labor  and  analysis  are  set  forth  from  the  collecting  and 
collating  of  data  involved  in  burner,  furnace,  and  fuel 

vii 


viii  PREFACE 

oil  tests,  hitherto  appearing, in  disconnected  form  and 
in  widely  varying  sources.  In  the  third  subdivision 
the  authors  have  given  definite  suggestions  for  fuel 
oil  tests — largely  suggestions  recently  presented  per- 
sonally by  the  authors  at  the  invitation  of  the  Power 
Test  Committee  of  the  American  Society  of  Mechan- 
ical Engineers  at  a  hearing  of  the  Committee  in  New 
York  City  for  the  purpose  of  standardizing  the  rules 
for  boiler  tests  where  oil  is  used  as  a  fuel. 

The  many  illustrative  problems  that  have  been 
worked  out  in  the  chapters  on  steam  engineering  and 
boiler  economy  are  based  upon  the  data  obtained  from 
the  latest  edition  of  Marks  &  Davis'  "Tables  and 
Diagrams  of  the  Thermal  Properties  of  Saturated  and 
Superheated  Steam,"  published  by  Longmans,  Green 
&  Company,  which  may  be  purchased  through  any 
reputable  book  dealer  for  the  sum  of  one  dollar.  For  a 
careful  study  of  these  illustrative  examples  the  reader 
should  provide  himself  with  a  copy  of  these  steam 
tables,  although  this  is  not  necessary  for  most  of  the 
discussions  on  fuel  oil  and  furnace  design  as  treated 
in  the  text. 

The  six  beautiful  views  of  the  economy  measuring 
apparatus  installed  at  the  Long  Beach  Plant  of  the 
Southern  California  Edison  Company,  featured  in  this 
book,  are  extended  through  the  courtesy  of  R.  J.  C. 
Wood,  superintendent  of  generation  for  the  Southern 
Division  of  that  company. 

Throughout  the  work  the  authors  have  attempted 
to  set  forth  standard  practice  in  fuel  oil  and  steam 
engineering.  As  a  consequence  they  are  indebted  to 
a  large  group  of  manufacturers,  engineers  and  power 
plant  operators  for  their  timely  suggestions  in  point- 
ing out  and  developing  the  fundamental  laws  of  fuel 
oil  and  steam  engineering  practice  that  are  dwelt  upon 
in  this  work. 


ROBERT    SIBLEY. 
CHAS.  H.  DELANY. 


San  Francisco,  U.  S.  A. 
May  1,  1918 


CONTENTS 

CHAPTER    I                                     Page 
The  Modern  Power  Plant  for  Fuel  Oil  Consumption 1 

The  Storage  Tank — Pumps  for  Storage  Supply — The  Hot- 
Well  —  Feed-Water  Heaters  —  Feed- Water  Pumps — Econo- 
mizers— The  Boiler — The  Superheater — The  Separator — Re- 
ciprocating Engines  or  Steam  Turbines — Condenser — Wet 
Vacuum  Pumps — Dry  Vacuum  Pumps. 

CHAPTER    II 

Fundamental  Laws  Involved  in  Fuel  Oil  Practice 14 

Newton's  Laws  of  Motion— Three  Fundamental  Units  of 
Length,  Mass  and  Time— Velocity,  Acceleration,  and  Force 
Defined — Conception  of  Work  and  Power — Various  Types  of 
Energy  Employed  for  Useful  Work. 

CHAPTER    III 

Theory  of  Pressures 23 

The  Steam  Gage — The  Difference  Between  Absolute  Pres- 
sure and  Gage  Pressure — The  Column  of  Mercury — Vacuum 
Pressures  —  Confusion  in  Pressure  Units  —  Relationship  of 
Pressure  Units — Inches  of  Water  and  Pounds  Pressure  per 
Square  Inch — The  Thirty  Inch  Vacuum — The  Practical  Form- 
ula for  Conversion  of  Pressures  —  To  Reduce  Barometer 
Readings  to  the  Standard  Thirty  Inch  Vacuum — Corrections 
for  the  Brass  Scale  of  a  Barometer — Example — Corrections 
for  Altitude  and  Latitude. 

CHAPTER    IV 

Measurement   of   Temperatures 32 

Fixed  Points  for  Thermometer  Calibration — The  Various 
Temperature  Scales  Employed — Relationship  of  Fahrenheit 
and  Centigrade  Values — Relationship  of  Fahrenheit  and 
Reaumur  Values — Relationship  of  Centigrade  and  Reaumur 
Values — Methods  of  Temperature  Measurement — Estimation 
by  Flame  Color— The  Melting  Point  of  Metals  and  Alloys— 
The  Method  of  Immersion — The  Alcohol  and  Mercurial  Ther- 
mometers— The  Expansion  Pyrometer — Electrical  Thermom- 
eters— The  Radiation  Pyrometer — Standardization  and  Test- 
ing of  Thermometers — The  Stem  Correction. 

CHAPTER    V 

The  Elementary  Laws  of  Thermodynamics i ,. .  43 

The  Irrefutable  Experiments  of  Davy — Joule's  Complete 
Demonstration  of  the  Mechanical  Equivalent  of  Heat — The 
First  Law  of  Thermodynamics — Boyle's  Law — Charles'  Law 
— The  Absolute  Scale  —  The  Composite  Law  of  Gases  —  A 
Formula  for  Gas  Density — To  Compute  "R"  for  Any  Gas — 
Further  Illustrative  Examples. 

CHAPTER    VI. 

Water  and  Steam  in  Fuel  Oil  Practice 52 

Three  States  are  Possible  in  All  Bodies — The  Fundamental 
Principle  in  Steam  Engineering — Steam  Engineering  Still 
Supreme — The  Formation  of  Ice — Latent  Heat  of  Fusion — 

ix 


x  CONTENTS 

Page 

The  Formation  of  Steam — Latent  Heat  of  Evaporation — 
Other  Variations  Occur  with  Changes  of  Pressure — Data 
Easily  Taken  from  Steam  Tables — Total  Heat  of  Steam — 
Total  Heat  of  Dry  Saturated  Steam— Other  Instances  of  To- 
tal Heats. 

CHAPTER    VII 

The  Steam  Tables  in  Fuel  Oil  Practice ,. . .   61 

The  Steam  Tables  as  Adopted  in  this  Discussion — Recap- 
itulation of  Fundamental  Evaluations — Analysis  of  a  Typical 
Page  of  Steam  Tables — Temperatures  in  Fahrenheit  Units — 
Pressures  in  Absolute  Notation — Pressures  in  Atmospheres 
— Specific  Volume — Specific  Density — The  Heat  of  Liquid — 
The  Latent  Heat  of  Evaporation — Total  Heat  of  Dry  Satu- 
rated Steam  —  Internal  and  External  Work  —  Entropy  of 
"Water — The  Entropy  of  Evaporation — Total  Entropy — Tables 
for  Superheated  Steam. 

CHAPTER    VIII 

How  to  Compute  Boiler  Horsepower 72 

The  Meaning  of  the  Word  "Rating" — The  Development  of 
the  Word  "Horsepower" — The  Boiler  Horsepower — The  Con- 
version of  Boiler  Horsepower  to  Mechanical  Horsepower 
Units — The  Myriawatt  as  a  Basis  of  Boiler  Performance — 
Relationship  of  Boiler  Horsepower  and  Myriawatts — The 
Builder's  Rating — To  Compute  Actual  Boiler  Rating. 

CHAPTER    IX 

Equivalent  Evaporation  and  Factor  of  Evaporation. ........  79 

The  Standard  that  Has  Been  Adopted — Dry  Saturated  Steam 
— Wet  Saturated  Steam — Superheated  Steam — To  Compute 
the  Boiler  Horsepower. 

CHAPTER    X 

\  How  to  Determine  Quality  of  Steam . ., 85 

Dry  Saturated  Steam — Superheated  Steam — Computation  of 
Total  Heat  of  Superheated  Steam — Steam  Calorimeters — The 
Determination  of  Superheat — Determination  of  Moisture  in 
Saturated  Steam — The  Barrel  or  Tank  Calorimeter— Surface 
Condenser  Tank  Calorimeter. 

CHAPTER    XI 

The  Steam  Calorimieter  and  Its  Use  in  Fuel  Oil  Practice. .   93 

The  Chemical  Calorimeter — The  Throttling  Calorimeter — The 
Limitations  of  the  Throttling  Calorimeter — The  Electric 
Calorimeter  —  The  Separating  Calorimeter  —  Correction  for 
Steam  Used  by  Calorimeter — The  Sampling  Nipple — Conclu- 
sions on  Moisture  Measuring  Apparatus — Latent  Heat  of 
Evaporation — A  Second  Formula  for  Heat  of  Evaporation — 
Relationship  of  Specific  Volume  for  Superheated  Steam — A 
Simplified  but  Limited  Formula— Other  Relationships  Exist. 

CHAPTER    XII 

Rational  and  Empirical  Formulas  for  Steam  Constants . . .  102 

The  Value  of  Formulas  in  Steam  Engineering — Relation  Be- 
tween Temperature  and  Pressure  of  Saturated  Steam — The 
Total  Heat  of  Saturated  Steam — Regnault's  Formula — Hen- 
ning's  Formula — Latent  Heat  of  Evaporation — A  Second 
Formula  for  Heat  of  Evaporation — Relationship  of  Specific 
Volume  for  Superheated  Steam — A  Simplified  but  Limited 
Formula — Other  Relationships  Exist. 


CONTENTS  xi 

CHAPTER   XIII  Page 

The  Fundamentals  of  Furnace  Operation  in  Fuel  Oil 

Practice 107 

The  Fundamentals  of  the  Tea-Kettle  and  the  Boiler  are 
the  Same — Inefficiency  of  Tea-Kettle  Operation — Efficiency 
in  the  Modern  Steam  Boiler  a  Necessity — Efficient  Furnace 
Construction  of  Utmost  Importance — Fuels  Defined — An  Air 
Supply  Essential — Furnace  Operation — The  Fuel  Oil  Burner 
and  Its  Function — The  Path  of  the  Furnace  Gases — The 
Economizer  and  Its  Economic  Value — Quantity  of  Air  Re- 
quired—The Draft  Gage  and  Its  Principle  of  Operation- 
Apparatus  for  Determining  Ingredients  of  Outgoing  Chimney 
Gases — Draft  Regulating  Devices — The  Chimney. 

CHAPTER    XIV 
The  Boiler  Shell  and  Its  Accessories  for  Steam  Generation.  114 

The  Laws  of  Heat  Involved  in  Steam  Generation — The 
Principle  of  Operation  of  the  Steam  Boiler — Mathematical 
Equation  for  Heat  Transference — Mathematical  Law  for 
Total  Heat  Absorption — Relationship  of  Rate  of  Heat  Trans- 
fer— Necessity  for  Boiler  Accessories — Injector  or  Pump  for 
Feed  Water  Supply  —  Check  and  Non-Return  Valves — The 
Steam  Gage  and  the  Water  Gage — Manholes — Provision  for 
Expansion — The  Mud  Drum — Safety  Valve. 

CHAPTER    XV 

Boiler  Classification  in  Fuel  Oil  Practice 122 

The  Boiler  Drum  and  Tubes — Internally  and  Externally  Fired 
Boilers — The  Return  Tubular  Boiler — The  Fire  Tube  and  the 
Water  Tube  Boiler — Vertical  and  Horizontal  Types — Illus- 
trations of  Principles  of  Construction  and  Operation — The 
Babcock  and  Wilcox  Boiler— The  Parker  Boiler— The  Stirling 
Type — The  Heine  Type — Marine  Boilers. 

CHAPTER    XVI 

Fuel  Oil  and  Specifications  for  Purchase j 131 

Advantages  of  Crude  Petroleum  as  a  Fuel — Liquid  Fuels 
Classified — Physical  and  Chemical  Properties  of  Oil — Odor 
and  Color — Moisture — Sulphur,  Gas  and  Other  Ingredients — 
Specifications  for  the  Purchase  of  Oil. 

CHAPTER    XVII 
Boiler  Room  Instructions  for  Fuel  Oil  Burning 140 

Inspection  Tests  Involved — Preliminary  Precautions — Con- 
necting Up  Boiler  Units — Low  Water  Encountered — Avoid 
Making  Repairs  Under  Pressure — Removal  of  Sediment — 
Keep  Out  Cylinder  Oil — Cooling  and  Cleaning  the  Boiler- 
Putting  Boiler  Out  of  Service. 

CHAPTER    XVIII 

How  to  Compute  Strength  of  Boiler  Shells  in  Fuel  Oil 

Practice , 147 

The  Strength  of  the  Solid  Plate— The  Strength  of  the  Net 
Section — Resistance  to  Shear — Resistance  to  Compression — 
Efficiency  of  the  Riveted  Section— Gage  Pressure  Necessary 
to  Burst  the  Solid  Boiler  Plate— Bursting  Pressure  of  the 
Seamt— The  Safe  Working  Pressure — Example  of  a  Lap 
Joint,  Longitudinal  or  Circumferential,  Double-Riveted. 


xii  CONTENTS 

CHAPTER   XIX                                  Page 
Furnaces  in  Fuel  Oil  Practice 157 

Fuel  Oil  Furnace  Operation  —  The  Commercial  Furnace — 
Regulation  of  Air — Importance  of  Air  Regulation — Service 
for  One  Boiler  Only. 

CHAPTER    XX 
Burner  Classification  in  Fuel  Oil  Practice 166 

The  Inside  Mixer — The  Outside  Mixer — An  Example  of  the 
Mechanical  Atomizer — .  The  Home-Made  Type  of  Burner — 
Front  Shot  and  Back  Shot  Burners — Quantity  of  Steam  Re- 
quired— Number  of  Men  Required  for  Operating  Oil  Fired 
Boilers — Caution. 

CHAPTER    XXI 
The  Gravity  of  Oils  in  Fuel  Oil  Practice. ., 176 

The  Method  of  the  Westphal  Balance  for  Exact  Measure- 
ment—Details of  Procedure — Computations  Involved. 

CHAPTER    XXII 
Moisture  Content  of  Oils 184 

Summary  of  Methods  Employed  in  Determining  the  Moisture 
Content — The  Approximate  Method  of  Treatment — Error  in 
Assuming  Percentage  by  Weight  is  Same  as  Percentage  by 
Volume. 

CHAPTER    XXIII 
Determination  of  Heating  Value  of  Oils 191 

An  Approximate  Method  Based  on  the  Baume  Scale — Du- 
long's  Formula  Based  on  the  Ultimate  Analysis — The  Fuel 
Calorimeter — The  Parr  Calorimeter — The  Principle  of  Opera- 
tion— Detailed  Operation  of  the  Parr  Calorimeter — Prelimin- 
ary Precautions — The  Explosion  of  the  Charge  and  the  Tak- 
ing of  Temperatures — The  Correction  for  Temperature  Read- 
ings— Higher  and  Lower  Heating  Value. 

CHAPTER    XXIV 
Chimney  Gas  Analysis  203 

The  Taking  of  the  Flue  Gas  Samples  and  Analysis — To 
Ascertain  the  Carbon  Dioxide  Content  of  a  Flue  Gas — To 
Ascertain  the  Oxygen  Content  of  a  Flue  Gas — To  Ascertain 
the  Carbon  Monoxide  Content  of  a  Flue  Gas — To  Ascertain 
the  Nitrogen  Content  of  a  Flue  Gas — An  Approximate  Check 
on  the  Orsat  Analysis — Chemical  Formulas  for  Preparing 
the  Absorption  Solutions — The  Hemphel  Apparatus  for  De- 
termining the  Hydrogen  Content — Conclusion  on  the  Orsat 
Analysis. 

CHAPTER    XXV 
Analysis  by  Weight,  and  Air  Theoretically  Required  in 

Fuel  Oil  Furnace 210 

Relationship  of  a  Component  Weight  to  the  Whole — Funda- 
mental Laws  Involved — A  Concrete  Rule  for  Conversions — 
Weight  of  Air  Theoretically  Required  for  Perfect  Fuel  Oil 
Combustion  —  Correction  for  Hydrogen  Appearing  in  Fuel 
Analysis — Oxygen  Theoretically  Required  for  Fuel  Combus- 
tion— Air  Required  per  Pound  of  Fuel  Burned. 

CHAPTER    XXVI 
Computation  of  Combustion  Data  from  the  Orsat  Analysis. 218 

Air  Actually  Supplied  to  Furnace  per  Pound  of  Fuel  Burned 
— An  Illustrative  Example — A  Second  Formula  for  Ascer- 
taining Air  Actually  Admitted  to  the  Furnace — Weight  of 
Dry  Flue  Gas  per  Pound  of  Fuel — Ratio  of  Air  Drawn  Into 
Furnace  to  that  Theoretically  Required. 


CONTENTS  xiii 

CHAPTER    XXVII  Page 

Weighing  Water  and  Oil 230 

Volumetric  Method  of  Measurement — Method  of  Standard- 
ized Platform  Scales — Weighing  of  the  Oil — Sampling  the 
Oil  Supply — General  Sampling  of  Fuel  Oil  for  Purchase — 
Sampling  with  a  Dipper  —  Continuous  Sampling  —  Mixed 
Samples. 

CHAPTER    XXVIII 

Measurement  of  Steam  Used  in  Atomization 236 

Mathematical  Expression  for  Flow  of  Steam — Apparatus 
Employed  in  Measuring  Steam  in  Atomization — Calibration 
of  Orifice — Numerical  Illustration. 

CHAPTER    XXIX 

The  Taking  of  Boiler  Test  Data .241 

The  Object — The  Instructions  for  Boiler  Tests — The  Test  for 
Efficiency  Under  Normal  Rating — Time  of  Duration  of  Test 
— The  Beginning  and  Stopping  of  a  Test — The  Weighing  of 
the  Water — The  Heat  Represented  in  the  Steam  Generated 
— The  Oil,  Its  Measurement  and  Analysis — The  Steam  Used 
in  Atomization — The  Boiler  Efficiency — The  Overload  Test 
— The  Quick  Steaming  Test — Observations  Necessary — Pres- 
sure Readings — Temperature  Readings — The  Flue  Gas  An- 
alysis— The  Test  as  a  Whole. 

CHAPTER    XXX 

Preliminary  Tabulation  and  Calculation  of  Test  Data 249 

The  Log  Sheet  for  Weighing  the  Water — Log  Sheet  for  the 
Fuel  Oil  Fed  to  Furnace— Other  Data  to  be  Taken — The 
General  Log  Sheet— The  Plotting  of  the  Test  Data. 

CHAPTER    XXXI 

The  Heat  Balance  and  Boiler  Efficiency 255 

Total  Heat  Absorbed  by  Boiler — Heat  Absorbed  by  Boiler 
for  Atomization — Net  Heat  Absorbed  by  Boiler  for  Power 
Generation — Loss  Due  to  Moisture  in  the  Fuel — Loss  Due 
to  Moisture  Formed  by  Burning  Hydrogen — Loss  Due  to 
Heat  Carried  Away  in  Dry  Gas — Loss  Due  to  Incomplete 
Combustion — Loss  Due  to  Evaporating  Steam  for  Atomiza- 
tion— Loss  Due  to  Superheating  Steam  Used  for  Atomiza- 
tion— Total  Loss  in  Atomization — Loss  Due  to  Moisture  in 
Entering  Air  —  Stray  Losses  —  Summary  of  Heat  Balance 
— Net  Boiler  Efficiency — Boiler  Efficiency  as  a  Steaming 
Mechanism — Summary  of  Data  Used. 

CHAPTER    XXXII 

Summary  of  Suggestions  for  Fuel  Oil  Tests  and  Their 

Tabulation    265 

Efficiency  for  Oil  Fired  Boilers  Defined — Tabulation  of  Fuel 
Oil  Test  Data— Principal  Data  and  Results  of  Boiler  Test. 

CHAPTER    XXXIII 

The  Use  of  Evaporative  Tests  in  Increasing  Efficiency 

of  Oil  Fired  Boilers 270 

Furnace  Arrangement — Oil  Burners — Draft — Flue  Gas  An- 
alysis for  Maximum  Efficiency — Regulation — Records. 


xiv  CONTENTS 

APPENDIX    I  Page 

Illustrative  Problems    279 

Thirty-three  Examples  Solved  in  Detail,  Illustrating  the 
Computations  Involved  in  Economy  Tests  for  Oil  Fired 
Boilers. 

APPENDIX    II 

Conclusions  and  Recommendations  on  Petroleum 292 

The  Summary  of  a  Comprehensive  Investigation  on  Crude 
Petroleum  undertaken  by  a  Committee  of  the  California 
State  Council  of  Defense. 

APPENDIX    III 

Helpful  Factors  in  Fuel  Oil  Study  and  Conservation 311 

Herein  may  be  found  a  discussion  of  the  various  state  and 
federal  aids  that  have  been  established  to  forward  the  study 
of  efficient  use  of  fuel  oil  and  its  conservation. 

Index    .  ..- 314 


DEDICATION 

To  the  University  of  California  and  its  splendid  traditions 
whatever  is  good  and  helpful  within  these  pages  is  affection- 
ately dedicated  by  the  authors. 


A  LAKEVIEW  GUSHER  — TO  SAVE  IS  TO  SERVE 

A  huge  fuel  oil  gusher  with  a  capacity  of  ten  thousand  barrels  daily 
was  tapped  recently  by  the  Standard  Oil  Company  in  California,  and 
not  a  drop  lost.  A  thorough  knowledge  of  the  fundamental  principles 
involved  in  fuel  oil  and  steam  engineering  practice  is  another  powerful 
factor  for  good  in  meeting  the  present  fuel  shortage  and  in  putting 
the  three  hundred  and  fifty  million  barrels  of  this  product  now  mined 
annually  in  the  United  States  to  its  highest  and  most  economic  use. 


FUEL  OIL  AND  STEAM 
ENGINEERING 

CHAPTER  I 

THE  MODERN  POWER  PLANT  FOR  FUEL  OIL 
CONSUMPTION 

H  E  enormous  growth  of 
the  e  1  e  c  t  r  i  c  ,a  1  industry 
throughout  the  world  dur- 
ing the  past  decade  has 
entirely  revolutionized 
methods  of  power  develop- 
ment. Especially  is  this 
true  west  of  the  Rocky 
Mountains,  where  gigantic 
natural  water  powers  have 
been  put  to  a  useful  pur- 
pose. Owing  to  the  fact, 
however,  that  most  of  the 
western  streams  show  a 
great  variation  in  flow  in 
the  different  seasons  of 
the  year,  it  is  not  always 

possible  to  depend  solely  upon  waterpower  for  the  sup- 
ply of  electrical  energy.  In  recent  years  the  advent  of 
crude  petroleum  upon  the  Pacific  Coast,  representing  a 
total  annual  production  of  over  one  hundred  million 
barrels,  has  made  it  possible  when  rainfall  or  water 
supply  is  lacking  to  economically  supply  the  needed 
power.  During  certain  hours  of  the  day,  too,  when  the 
so-called  peak  load  conditions  are  to  be  met  by  a  cen- 
tral station,  additional  electrical  energy  over  that  pos- 
sible to  supply  from  the  hydroelectric  station  is  found 
to  be  necessary.  Hence,  the  steam  power  plant,  con- 


A  20,000  h.p.  Curtis  Turbine  In- 
stalled  in   San   Francisco 


s.    ! 

c 


S-o^-S  c  <D  w 

i|  till  II 


, 


THE  MODERN  POWER  PLANT     ,   ,      ^,:  ;3; 

sisting  of  large  concentrated  units,  is  now  recognized 
as  an  indispensable  auxiliary  to  continuity  of  service. 

In  order  that  there  should  be  no  excessive  loss 
in  distribution,  these  concentrated  steam  power  units 
are  usually  found  in  the  heart  of  the  great  distribution 
centers.  Especially  is  this  true  where  abundance  of 
circulating  or  cooling  water  may  be  obtained.  Thus 
we  find  in  Central  California,  Station  A  and  Station  C 
of  the  Pacific  Gas  &  Electric  Company,  and  the  Fruit- 
vale  Station  of  the  Southern  Pacific  Company,  all  sit- 
uated in  the  distributing  centers  of  San  Francisco  and 
its  immediate  vicinity.  In  the  Los  Angeles  district  we 
find  that  the  Redondo  and  Long  Beach  plants  of  the 
Southern  California  Edison  Company,  owing  to  the 
lack  of  abundant  cooling  water  near  the  distribution 
center  are  situated  at  a  distance  from  it  of  some  fifteen 
or  twenty  miles. 

It  will  now  be  interesting  and  instructive  to  ex- 
amine the  details  of  a  typical  power  installation  of 
the  sort  just  hinted  at. 

First,  we  shall  describe  the  so-called  steam  cycle  or 
the  journey  of  the  steam-making  water  from  the  time 
it  enters  the  steam  boiler  until  it  has  passed  through 
the  turbine,  or  power  unit,  and  returned  again  to  the 
boiler;  secondly,  we  shall  consider  the  circulating 
water  which  is  necessary  in  large  quantities  to  convert 
the  exhaust  steam  back  again  into  water;  and  thirdly, 
we  shall  also  touch  briefly  upon  the  journey  of  the  oil 
from  the  time  it  leaves  the  cars  at  the  sidetrack  until 
it  disappears  from  the  chimney  as  a  flue  gas.  We  shall 
also  touch  briefly  upon  the  general  size  and  functions 
of  apparatus  employed  to  accomplish  these  results. 

The  Steam  Cycle 

The  Storage  Tank.  The  supply  of  water  for 
ste.aming  purposes  is  usually  brought  to  a  make-up  or 
storage  tank  from  supply  wells  either  on  the  imme- 
diate premises  or  nearby  property.  If  these  are  not 
found,  it  is  brought  from  rivers,  lakes,  or  other  bodies 


frtfEL  'OIL1  'AND  STEAM  ENGINEERING 


*m'YiTe*v^cimty;-Vf*irrmany  cases  is  purchased  from 
some  water  company  supplying  the  municipality.  The 
storage  tanks  are  varied  in  size,  shape  and  capacity 
from  a  small  tank,  used  as  a  receiver  and  hot-well,  to  a 
number  of  tanks,  large  and  small,  used  for  storage 
purpose  only. 

The  use  of  storage  tanks  depends  upon  the  source 
and  quantity  of  water  supplied  and  the  load  carried 
by  the  plant.  Where  there  is  a  steady  and  positive 
source  of  supply,  the  tank  may  be  of  small  capacity. 
In  some  cases  where  the  supply  is  small  and  the  stor- 
age at  different  periods  is  unfit  for  use,  larger  storage 
and  settling  tanks  are  required,  and  at  times  even  fil- 
tration and  cleaning  tanks  also  are  employed. 

Pumps  for  Storage  Supply.  The  tanks  above 
alluded  to  are  filled  either  by  pumps,  gravitation  flow, 
siphons,  or  piping  from  a  water  company's  main. 
There  seems  to  be  no 
standard  type  of 
pump.  Both  recip- 
rocating and  rotary 
appear  in  standard 
practice.  On  the 
other  hand,  many 
plants  have  wells  and 
water  is  lifted  by  air 
pressure.  This,  on 
account  of  the  total 
absence  of  working- 
parts,  is  particularly 
useful,  where  there 
are  a  number  of  scat- 
tered wells,  and,  also, 

When    it    becomes  Measuring-   and  Purifying  Tank 

necessary   to   handle  for  water  supply  at  Re- 

dirty  water,  that  is, 

water  containing  sand,  grit,  and  dirt  in  suspension. 
This  air  lift  consists  of  a  partially  submerged  water 
pipe  and  an  air  supply  pipe.  The  casing  of  the  well 
is  driven  below  the  lift  pipe.  The  lift  pipe  is  set 


THE  MODERN  POWER  PLANT  5 

in  the  well  either  with  air  surrounding  it  between  the 
pipe  and  the  casing  or  with  a  cap  over  the  casing, 
making  the  space  in  the  casing  air-tight.  In  some  in- 
stances the  well  casing  is  used  directly  as  the  lift  pipe. 

The  Hot- Well.  The  water  from  the  storage  tanks 
is  either  pumped  or  is  caused  to  flow  by  gravity  to  a 
socalled  hot-well.  The  hot-well  is  a  tank  which  stores 
the  water  before  it  passes  to  the  feed-water  heater.  It 
receives  water  from  the  condenser  and  admits  an  addi- 
tional supply  from  the  storage  tanks  to  meet  the 
needs  of  steam  generation. 

Feed-Water  Heaters.  From  the  hot-well,  water 
is  taken  into  the  feed-water  heater.  The  function  of  a 
feed-water  heater  is  to  heat  the  entering  water  to  a 
temperature  approximating  that  of  evaporating  condi- 
tions in  order  to  keep  the  boiler  at  as  even  a  tempera- 
ture as  possible  and  at  the  same  time  to  put  the 
exhaust  steam  from  the  auxiliary  apparatus  to  some 
useful  purpose. 

Feed-water  heaters  are  divided  into  two  general 
types  :  open  and  closed.  In  the  open  heater  the  steam 
comes  in  direct  contact  with  the  cooling  water,  and  it 
there  is  a  sufficient  quantity  of  exhaust  steam,  it  raises 
the  water  to  212  deg.  F.,  the  excess  steam  passing  to 
the  atmosphere.  In  a  closed  heater,  on  the  other  hand, 
the  water  and  steam  do  not  come  in  contact  with  each 
other,  the  water  usually  passing  through  a  set  of  tubes 
while  the  steam  is  brought  in  contact  with  the  outside 
of  the  tubes. 

Feed-Water  Pumps.  The  water  is  forced  into  the 
boiler  by  means  of  feed-water  pumps,  which  may  be 
either  ordinary  reciprocating  or  multistage  centrifugal 
pumps,  the  latter  being  especially  adapted  to  large 
power  plants. 

In  steam  plants  where  closed  feed-water  heaters 
are  used,  the  boiler  feed  pumps  are  placed  before  the 
heater,  thus  pumping  through  the  heater  to  the  boiler. 
When  open  feed-water  heaters  are  used,  however,  the 
boiler  feed  pumps  are  placed  between  the  heater  and 
the  boiler. 


6  FUEL  OIL  AND  STEAM  ENGINEERING 

Economizers.  Economizers  are  sometimes  in- 
stalled as  well  as  feed-water  heaters.  The  economizer 
is  a  series  of  pipes  through  which  the  feed-water 
passes,  placed  in  the  path  of  escaping  gases  from  the 
boiler  furnace. 

The  Boiler.  The  boiler  next  receives  the  water 
from  these  heaters  and  converts  it  into  steam  at  the 
desired  pressure  and  temperature.  The  main  types  of 


The  Redondo  Power  Plant  of  the  Southern  California  Edison 
Company  with  Oil  Storage  Tanks 

boilers  are  water  and  fire  tube.  Modern  practice  in- 
dicates a  decided  preference  for  water  tube  boilers.  A 
water  tube  boiler  consists  of  steam  and  water  drums 
placed  on  the  top  and  a  mud  drum  placed  below,  the 
two  being  connected  by  a  series  of  tubes  filled  with 
water  or  steam.  The  fire  is  below  these  tubes,  and 
the  heat  from  the  furnace  is  made  to  pass  around 
them  several  times  by  means  of  baffles  or  partitions, 
thus  supplying  heat  for  steam  generation. 


THE  MODERN  POWER  PLANT  7 

The  Superheater.  The  water  being  thus  con- 
verted into  saturated  steam  by  heat  from  the  furnace 
of  the  boiler,  is  next  passed  through  a  series  of  tubes 
known  as  a  superheater.  These  tubes  are  exposed  in 
a  heated  portion  of  the  gas  passage  and  thus  the  steam 
is  raised  to  a  point  much  higher  than  its  saturated 
temperature. 

The  Separator.  From  the  superheater  the  steam 
passes  through  suitable  piping  to  a  separator,  placed 
between  the  boiler  and  the  engine,  or  between  the  boil- 
er and  the  turbine.  This  separator  is  placed  as  near 
the  power  unit  as  possible  in  order  to  remove  all  con- 
densed steam  that  may  be  found  in  the  pipes.  One 
form  of  separator  performs  its  function. by  quickly  re- 
versing the  direction  of  the  flow  of  steam,  thus  depos- 
iting the  water  into  a  drip  which  is  drained  off  into 
the  condenser.  Another  form  gives  a  rotary  motion  to 
the  entering  steam  thus  hurling  particles  of  water 
off  by  centrifugal  force  and  collecting  it  in  proper 
receptacles.  Again,  baffle  plates  are  at  times  em- 
ployed wherein  the  flow  is  interrupted  by  corrugated 
or  fluted  plates,  and  the  particles  of  water  adhering  to 
these  are  then  drained  off. 

Reciprocating   Engine  or   Steam  Turbines.     The 

steam  next  goes  from  the  separator  to  the  main  power 
generating  units.  The  main  units  in  earlier  practice 
were  reciprocating  engines ;  in  modern  installations 
they  are  steam  turbines. 

Reciprocating  engines  may  be  divided  into  sev- 
eral classes,  the  details  of  which  will  not  be  outlined 
in  this  general  discussion.  Suffice  it  to  say,  however, 
that  the  main  principle  upon  which  reciprocating  en- 
gines act  is  that  steam  enters  a  cylinder  under  pressure, 
thus  forcing  ahead  a  piston  which  is  connected  to  a 
crank  arm,  thereby  causing  rotation  and  the  conse- 
quent generation  of  power. 

Steam  turbines  are  divided  into  two  general 
classes  known  as  impulse  turbines  and  reaction  tur- 
bines. In  the  impulse  turbine  steam  is  allowed  to 
expand  in  passing  through  a  nozzle,  thus  causing  the 


8  FUEL  OIL  AND  STEAM  ENGINEERING 

steam  to  travel  at  an  enormous  velocity.  The  steam, 
having  acquired  this  velocity  by  impinging  against 
movable  blades,  causes  rotation  and  the  consequent 
generation  of  power.  In  the  reaction  turbine,  how- 
ever, the  steam  is  allowed  to  enter  the  buckets  or  ro- 
tating vanes  at  a  comparatively  low  velocity.  These 
vanes  are  so  designed  that  the  steam  may  expand  in 
this  movable  portion  and  by  means  of  its  expanding 
pressure  cause  rotation  and  hence  the  generation  of 
power. 

Turbines  as  a  general  rule  have  two  other  classi- 
fications, known  as  vertical  and  horizontal.  The  ver- 
tical turbine  revolves  upon  a  vertical  shaft,  which  is 
supported  at  the  bottom  by  a  thin  film  of  oil  under 
the  high  pressure  of  about  900  to  1000  Ib.  per  in.  The 
horizontal  turbine,  however,  as  the  name  indicates, 
rotates  on  a  horizontal  axis,  and  is  supported  in  the 
usual  manner  by  means  of  suitable  bearings. 

Condenser.  From  the  steam  turbine,  the  steam, 
having  expanded  to  its  useful  limit,  is  dropped  into 
an  incasement  through  which  cool  water  is  being 
passed.  Upon  coming  in  contact  with  this  cooling  de- 
vice the  steam  is  again  converted  into  water.  The 
apparatus  performing  this  function  is  known  as  a  con- 
denser, there  being  two  general  classes :  surface  con- 
densers and  jet  condensers. 

In  the  surface  condenser  the  steam  from  the  tur- 
bine and  the  cooling  water  from  a  nearby  source  of 
supply  do  not  come  into  direct  contact,  but  the  cooling 
water  is  passed  through  inclosed  tubes  around  which 
the  steam  from  the  turbine  or  power  unit  is  made  to 
pass.  This  type  of  condenser  is  used  where  large 
quantities  of  water  are  available  for  cooling  purposes 
but  not  for  steaming  purposes.  Thus  the  use  of  salt 
water,  the  only  abundant  supply  available  for  ocean- 
going steamships  and  large  power  plants  situated  near 
the  ocean,  makes  a  condenser  of  the  surface  type  im- 
perative for  such  installation. 

In  the  jet  condenser  the  supply  of  cooling  water  is 
allowed  to  mingle  with  the  steam  as  it  drops  from  the 


THE  MODERN  POWER  PLANT  9 

turbine  or  power  unit  and  thus  the  steam  is  at  once 
condensed  into  water.  The  water  from  the  jet,  being 
pure  in  supply,  may  be  used  in  the  hot-well  for  steam 
purposes. 

Wet  Vacuum  Pumps.  The  condensed  steam,  now 
in  the  form  of  water,  is  pumped  from  the  condenser 
back  again  into  the  hot-well  by  means  of  what  is  known 
as  the  wet  vacuum  pump.  This  pump  may  be  either  a 
reciprocating  or  rotary  pump,  but  in  general  the  ro- 
tary type  seems  to  have  the  preference.  Thus  the 
entire  cycle  for  the  water  is  traced  from  the  make-up 
tank  or  hot-well  through  the  boiler  and  power  unit, 
and  back  again  to  the  hot-well. 

Dry  Vacuum  Pumps.  The  condenser  also  has  a 
dry  vacuum  pump  in  order  to  remove  from  the  steam 
space  within  any  air  which  may  have  been  trapped 
from  the  steam  generated  in  the  boiler.  This  pump 
is  nothing  more  nor  less  than  an  ordinary  air  com- 
pressor so  designed  that  it  will  take  air  at  a  very 
low  pressure  and  compress  it  up  to  atmospheric  pres- 
sure, thus  pumping,  as  it  were,  into  the  outer  atmos- 
phere such  air  as  may  have  been  entrapped  in  the 
condenser. 

Circulating  Water  Cycle 

From  the  description  of  the  working  of  the  con- 
denser it  is  seen  that  cooling  water  is  necessary  to 
convert  the  steam  in  the  condenser  back  again  into 
water.  This  cooling  supply  is  known  as  circulating 
water,  which  is  usually  taken  through  pipes  from 
some  large  natural  lake  or  river  or  even  the  ocean  and 
forced  by  means  of  reciprocating  or  rotary  pumps 
through  the  condenser  back  again  into  the  open.  The 
water  in  its  journey  is  raised  in  temperature  in  the 
surface  condenser  system  from  15  to  20  deg.  F.  above 
its  entering  condition. 

The  Oil  Cycle 

Of  general  interest  to  boiler  testing  and  operation 
is  the  oil  cycle  employed  in  the  utilization  of  crude 


10  FUEL  OIL  AND  STEAM  ENGINEERING 


Cross-section  of  the  Babcock  &  "Wilcox  Boiler — Oil-fired 

petroleum  as  a  fuel.    Let  us  then  briefly  trace  the  jour- 
ney the  oil  makes  through  the  modern  power  plant. 

In  the  larger  installations  the  oil  is  sidetracked 
from  the  main  railway  line  in  specially  designed  cars 
or  barges  for  its  easy  conveyance  and  handling.  An  oil 
heater,  consisting  of  a  coil  through  which  steam  is 
passing,  is  lowered  into  the  car  in  order  to  warm  the 
oil  as  it  is  drawn,  thus  making  its  transfer  considerably 


The  Staples  &  Pfeifer  Fuel  Oil  Atomizer 


THE  MODERN  POWER  PLANT  11 

easier.  By  means  of  a  pump  this  oil  is  then  taken  into  a 
storage  tank  which  may  be  of  wood,  steel,  or  concrete, 
depending  upon  the  permanence  of  design  thought 
necessary.  From  this  storage  tank  the  oil  is  pumped 
through  oil  heaters,  the  exhaust  from  the  pumps  in 
many  cases  being  utilized  in  still  further  heating  the 
oil  before  it  reaches  the  burner  or  atomizer. 

An  atomizer  is  a  device  used  to  vaporize  or  spray 
the  oil  into  the  furnace  in  fine  globules  or  particles. 
This  is  accomplished  by  means  of  steam,  air,  or  some 
mechanical  contrivance.  Immediately  upon  its  being 


The  Peabody  Fuel  Oil  Atomizer 

sprayed  into  the  furnace  carefully  designed  air  regu- 
lating devices  admit  sufficient  air  from  below  to  cause 
perfect  combustion.  The  heat  thus  liberated  from 
the  oil  due  to  its  burning  with  the  oxygen  is  caused 
to  flow  in  and  around  numerous  tubes  through  which 
water  is  passing  and  thus  this  water  is  converted  into 
steam.  After  passing  these  tubes  the  heated  flue  gases 
brought  to  life  by  the  burning  of  the  oil  with  the  enter- 
ing air  are  then  conducted  through  the  chimney  out 
into  the  atmosphere. 

An -interesting  detail  in  the  boiler  plant  is  the 
automatic  system  of  firing  employed  to  minimize  labor 
and  improve  efficiency  in  burning  the  oil.  The  Moore 
patent  fuel  oil  regulating  system  which,  from  one  cen- 
tral point,  controls  the  oil  supply,  the  atomizing  steam 


12 


FUEL  OIL  AND  STEAM  ENGINEERING 


and  the  amount  of  air  to  each  furnace,  is  an  interesting 
example. 

This  regulator  is  actuated  by  the  pressure  from 
the  main  steam  header  so  that  any  variation  in  steam 
requirements  will  cause  a  corresponding  change  in 
the  amount  of  oil  fired,  due  to  an  increase  or  decrease 
in  the  steam  supply  to  the  oil  pumps  and  atomizers. 
Any  fluctuation  in  steam  pressure  operates  a  gov- 


Steam    to   Burner  Regulator 

ernor  whose  power  arm  controls  a  bleeder  valve  on  the 
oil  pump  discharge  line,  thus  cutting  off  the  oil  supply 
if  the  steam  pressure  is  too  high  and  rcduuktg  it  if  too 
low.  Any  change  in  pressure  in  the  oil  main,  in  turn, 
controls  the  amount  of  steam  for  atomizing  and  of  air 
for  burning  the  oil. 

It  is  found  that  a  simple  straight  line  relationship 
exists  between  the  amount  of  steam  required  for  atom- 
izing the  oil  and  the  amount  of  oil  burned.  Two  dia- 
phragms are  employed  to  balance  the  pressures  in 
the  oil  main  and  in  the  steam  main  connected  to  the 
burners,  these  pressures  in  this  instance  being  200  Ib. 
and  80  Ib.  respectively.  Any  difference  in  oil  pressure 


THE  MODERN  POWER  PLANT  13 

operates  a  rotary  chronometer  valve  in  the  steam  main 
through  the  medium  of  a  fulcrum,  water  motor  and 
lever  connecting  rod.  Likewise  the  variance  in  oil 
pressure  actuates  a  counterweighted  rock  shaft  which 
moves  the  dampers  so  as  to  vary  the  amount  of  air 
admitted  for  combustion. 

General  Summary 

Thus  it  is  seen  in  this  brief  description  that  by 
using  crude  oil  as  fuel  three  main  cycles  of  operation 
are  synchronously  carried  on  in  the  modern  power 
plant.  Briefly  summarizing,  these  are  as  follows : 

Water  is  taken  through  the  boiler,  converted  into 
steam  and  passed  through  a  driving  mechanism,  after 
which  the  steam  is  reconverted  into  water  and  this 
water  again  passed  through  the  boiler.  Simultaneously 
with  this  action  water  is  being  pumped  through  the 
circulating  system  to  bring  about  the  conversion  of  the 
steam  from  the  power  unit  into  water.  Again  oil  in  a 
finely  atomized  or  gaseous  state  is  being  fed  through 
pipes  into  the  furnace,  where  it  immediately  combines 
with  the  proper  quantity  of  oxygen  from  the  entering 
air,  and  thus  sufficient  heat  is  liberated  from  the  oil 
to  evaporate  the  water  supply  of  the  boiler  into  steam 
for  power  generation. 


CHAPTER  II 

FUNDAMENTAL  LAWS  INVOLVED  IN  FUEL 
OIL  PRACTICE 


N  the  awful  throes  of  the 
French  Revolution  and 
the  immediate  years  fol- 
lowing, the  old  saying 
that  "every  cloud  has  its 
silver  lining"  proved  true 
in  certain  lines  of  scien- 
tific advancement,  for  the 
metric  system  of  units 
was  conceived  and  put 
into  practice  at  that 
period. 

Our  modern  system  of 
Arabic  numerals,  now 
practi  c  a  1  1  y  universally 
ad°P.ted  throughout  the 
civilized  world,  required 
over  five  hundred  years  of  human  fumbling  and 
competition  with  the  old  Roman  method  of  nu- 
merical representation,  before  a  complete  replacement 
was  accomplished,  so  intensely  are  we  all  creatures 
of  habit  and  slaves  to  tradition. 

And  so  it  is  that  although  a  period  of  a  century 
is  now  passed  since  the  institution  of  the  metric  sys- 
tem, modern  central  station  engineering  practice  is 
still  entangled  with  Fahrenheit  scales,  'boiler  horse- 
powers, mechanical  horsepowers,  myriawatts,  Baume 
scale  readings  for  gravity,  inches  of  mercury  vacuum, 
pounds  pressure  per  sq.  in.,  feet  and  inches  —  all  units 
related  so  unscientifically  and  empirically  as  to  cause 
bewilderment  in  itself. 


MeCcha^csaunEHserfty 


14 


FUNDAMENTAL  LAWS  15 

In  the  following  discussion,  however,  the  authors 
will  endeavor  to  set  forth  the  various  units  of  ex- 
pression in  such  simple  language  that  it  is  hoped  that 
even  the  beginner  may  have  little  difficulty  in  under- 
standing their  meaning.  Let  us  first  get  some  concep- 
tion of  the  need  for  units  of  measurement  and  how 
such  units  are  fundamentally  conceived. 

Newton's  Laws  of  Motion. — Fable  has  it  that  Sir 
Isaac  Newton,  when  a  boy  in  England,  lying  one  day 
under  an  apple  tree  and  gazing  upward,  saw  an  apple 
fall  to  the  ground.  The  contemplation  of  this  phenom- 
enon led  Newton  to  give  to  the  world  three  funda- 
mental laws  upon  which  modern  engineering  science  is 
built.  Briefly  stated  these  laws  are  as  follows : 

Law  1.  Every  body  continues  in  a  state  of  rest  or  a  state 
of  uniform  motion  in  a  straight  line  'except  in  so  far  as  it 
may  be  compelled  by  force  to  change  that  state. 

Law  2.  Change  of  motion  is  proportional  to  impressed 
force  and  takes  place  in  the  direction  of  the  straight  line 
in  which  the  force  acts. 

Law  3.  To  every  action  there  is  always  an  equal  and 
contrary  reaction;  or  the  mutual  actions  of  any  two  bodies 
are  always  equal  and  oppositely  directed. 

Hence  a  force  is  said  to  be  acting  according  to 
Law  1  whenever  the  physical  conditions  are  such  that 
velocity  is  changed  in  magnitude  or  direction.  Thus, 
when  a  train  of  cars  is  started  or  stopped,  a  force  is 
necessary  to  cause  this  phenomenon,  and  this  is  evi- 
dently a  change  in  the  magnitude  of  the  velocity,  un 
the  other  hand,  in  the  rotation  of  a  fly  wheel,  the  ve- 
locity may  change  solely  in  direction  without  a  change 
in  magnitude,  and  yet  a  force  be  necessary  to  maintain 
its  parts  in  equilibrium.  Hence  a  force  may  be  con- 
sidered as  a  push  or  a  pull  acting  upon  a  definite  por- 
tion of  a  body,  but  this  tendency  may  be  counteracted 
in  whole  or  in  part  'by  the  action  of  other  forces.  In 
the  latter  instance  the  force  is  usually  denoted  as  pres- 
sure, and  it  is  the  consideration  of  this  latter  case,  or 
the  consideration  of  pressures,  that  will  largely  concern 
our  attention  in  the  generation  of  steam  in  a  boiler. 


16 


FUEL  OIL  AND  STEAM  ENGINEERING 


Three  Fundamental  Units  of  Length,  Mass  and 
Time. — In  considering  Law  2,  it  is  seen  that  there  is 
some  inherent  property  in  matter  that  makes  it  difficult 
to  set  it  in  motion.  Physicists  have  defined  this  quality 
of  matter  as  being  the  inertia  of  a  body.  Inertia  is 
expressed  quantitatively  in  engineering  practice  in 
terms  of  its  mass,  which  is  measured  in  pounds.  In 
order  that  these  quantities,  force  and  mass,  now  intro- 
duced may  be  quantitatively  measured,  it  is  necessary 
to  have  some  fundamental  units  upon  which  to  base  our 
computations.  Three  units  only  are  fundamentally  re- 
quired;  namely,  a  unit  of  length,  a  unit  of  mass,  and  a 
unit  of  time.  Scien- 
tific practice  has  de- 
duced for  these  units 
the  centimeter,  the 
gram,  and  the  sec- 
ond, which  are  well 
known  and  need  no 
further  illustration. 
In  engineering  prac- 
tice, however,  espe- 
cially among  Eng- 
lish-speaking people, 
the  foot,  the  pound, 
and  the  second  seem 
to  be  in  almost  uni- 
versal usage.  We 
shall  consequently 
largely  express  our 
deductions  in  terms 
of  these  latter  units. 

Velocity,  Acceleration,  and  Force  Defined. — Hav- 
ing now  decided  upon  the  three  fundamental  units  of 
measurement,  let  us  look  into  other  fundamental 
definitions  and  secondary  units  to  be  employed. 

Since  engineering  science  must  deal  with  motion 
and  the  change  of  motion  per  unit  of  time,  it  is  neces- 
sary that  we  have  units  wherein  to  measure  them. 
Change  of  distance  per  unit  of  time  is  known  as  ve- 
locity and  is  expressed  in  feet  per  second.  A  change 


Electrical    Energy    from    Steam 
Turbine  in  San   Francisco 


FUNDAMENTAL  LAWS  17 

in  distance  may,  however,  be  undergoing  a  change,  and 
this  phenomenon  is  known  as  acceleration,  which  is 
measured  by  the  change  of  velocity  in  feet  per  second. 

Since  a  force  P  is  fundamentally  denned  as  being 
proportional  to  the  change  in  motion  of  a  body,  it 
follows  that  a  force  is  equal  to  a  constant,  M,  multi- 
plied by  the  change  in  motion,  or,  in  other  words, 
multiplied  by  the  acceleration,  a. 

When  M  is  in  pounds  mass  and  a  is  acceleration 
in  ft.  per  sec.  per  sec.,  the  force  P  is  measured  in 
poundals.  The  pound  force  is  the  unit,  however,  that 
has  'been  universally  adopted  in  engineering  practice. 
The  pound  is  such  a  force  as  will  give  to  a  pound  mass 
the  same  change  of  motion  per  second  as  is  acquired 
by  a  body  falling  freely  to  the  earth's  surface.  A  body 
falls  to  the  earth's  surface  with  an  acceleration  of  g  ft. 
per  sec.  per  sec.,  wherein  g  has  an  average  value  of 
about  32.16.  We  have  then  the  fundamental  mathe- 
matical expression  for  force  in  pounds  as  follows  : 

P^Ma  ..................................   (1) 

Whenever,  however,  it  is  necessary  to  ascertain 
the  mass  M  in  pounds  from  the  known  weight  W  of 
the  body  in  lb.,  it  is  necessary  of  course  to  divide  W 
by  g  in  order  to  ascertain  the  mass.  Thus  we  have  in 

W 
this  case  P  =  —   —a  ...........................  (la) 

g 

Thus,  if  an  automobile  weighing  3000  lb.  acceler- 
ates from  a  stand-still  to  forty  miles  per  hour  in  fif- 
teen seconds,  we  compute  the  force  required  to  accom- 
plish this  as  follows  : 

3000          40  X  5280 
P  =  -  X 


32.16       60X60X15 

Since  this  total  force  must  be  supplied  from  the 
engine  cylinder  this  now  gives  us  a  preliminary  clew 
as  to  how  the  total  engine  cylinder  area  is  to  be  pro- 
portioned. 


FUNDAMENTAL  LAWS  19 

Bodies  acquire  different  changes  of  motion  per 
second,  or,  in  other  words,  different  accelerations  at 
different  points  on  the  earth's  surface.  A  formula  has 
been  established  by  means  of  which  proper  corrections 
may  be  made.  A  concrete  illustration  of  this  will  ap- 
pear in  the  next  chapter  wherein  a  mercury  column  is 
used  to  measure  atmospheric  and  vacuum  pressures  at 
different  latitudes  and  altitudes. 

It  is  unfortunate  that  mass  and  force  have  the  same 
unit  of  expression,  for  they  are  definite  distinct  phys- 
ical concepts  and  should  be  carefully  distinguished  in 
order  to  avoid  confusion. 

Conception  of  Work  and  Power. — In  Law  2  we 
are  informed  that  the  change  of  motion  takes  place 
in  the  direction  of  the  straight  line  in  which  the  force 
acts.  It  is  often  convenient  to  note  quantitatively  the 
product  of  the  force  and  the  distance  through  which 
the  force  acts.  This  product  is  called  "work"  and  is 
numerically  computed  by  multiplying  the  force  in 
pounds  by  the  distance  in  feet  through  which  the  force 
acts.  The  resulting  computations  are  then  expressed 
in  foot-pounds  (ft.  lb.).  Thus,  if  the  mean  effective 
pressure,  P,  in  a  cylinder  is  measured  in  pounds  per 
sq.  in.  and  the  piston  has  an  area  of  A  sq.  in.,  it  follows 
that  the  total  force  or  pressure  acting  in  the  direction 
of  the  motion  of  the  piston  is  PA.  When  this  force  has 
pushed  the  piston  the  length  of  its  stroke,  L  ft.,  the 
work  accomplished  is  PLA  ft.  lb.,  since  this  is  the  pro- 
duct of  the  force  and  the  distance  through  which  the 
force  acts.  If  there  are  N  working  strokes  per  minute, 
the  ft.  lb.  of  work  accomplished  every  minute  are  now 
seen  to  be  PLAN. 

The  mention  of  the  words  "per  minute"  in  the  last 
statement  now  indicates  to  us  that  the  time  taken  to 
perform  a  given  quantity  of  work  in  engineering  prac- 
tice is  of  vast  importance.  Consequently  this  fact 
necessitates  still  another  unit  of  measurement,  name- 
ly that  of  power.  Power  is  defined  as  the  time  rate 
of  doing  work.  The  horsepower  is  the  basic  unit. 
When  550  ft.  lb.  of  work  are  performed  per  sec.,  or 
33,000  ft.  lb.  per  minute,  a  horsepower  is  said  to  be 


20 


FUEL  OIL  AND  STEAM  ENGINEERING 


developed.  Hence,  since  in  the  above  engine  cylinder 
PLAN  ft.  Ib.  per  min.  are  being  developed,  the  horse- 
power is  computed  as  follows : 

PLAN 
H.P.=-  - (2) 

33,000 

Thus,  in  Alameda,  California,  a  certain  Diesel  oil 
engine  has  a  piston  area  of  113.15  sq.  in.,  a  stroke  of  1.5 


The  Steam  Gage  Tester  Illustrates  the  Application  of  a  Funda- 
mental Law,  wherein  a  Pressure  is  Balanced  Against  the  Force 
Due  to  Gravity 

ft.,  a  mean  effective  pressure  of  77.3  Ib.  per  sq.  in., 
.and  each  cylinder  makes  125  working  strokes  per 
minute.  Hence,  each  cylinder  develops  . 

77.3X1.5XH3.15X125 

H.P.  = =  50.0 

33,000 

In  a  later  discussion  the  particular  power  units 
employed  in  steam  engineering  practice  will  be  con- 
sidered in  minute  detail,  such,  for  instance,  as  the 
horsepower,  the  boiler  horsepower,  and  the  myriawatt. 


FUNDAMENTAL  LAWS  21 

Various  Types  of  Energy  Employed  for  Useful 
Work. — Another  important  consideration  is  that  of  the 
physical  characteristic  of  a  body  Which  enables  it  to 
perform  work.  This  physical  quality  possessed  by  a 
body  which  enables  it  to  perform  a  definite  quantity  of 
work  is  spoken  of  as  its  energy.  Energy  then 'is  the 
capacity  for  work.  In  general  we  meet  with  two  great 
classes  of  energy.  One  is  that  of  kinetic  energy,  or 
energy  of  motion.  According  to  Law  2,  if  the  motion 
of  a  body  be  changed,  a  force  is  required.  Hence  a 
body  actually  in  motion  possesses  kinetic  energy.  The 
other  type  of  energy  is  known  as  potential,  or  energy 
of  position.  Thus  steam  moving  with  a  high  velocity, 
by  the  nature  of  its  kinetic  energy,  is  enabled  to  drive 
the  wheels  of  an  impulse  turbine.  On  the  other  hand, 
crude  petroleum  when  heated  so  that  it  will  unite  with 
the  oxygen  of  the  air  gives  out  energy  in  the  form  of 
heat,  which  may  be  caused  to  do  useful  work.  The 
energy  inherently  latent  in  the  crude  petroleum  is 
known  then  as  potential  energy.  Engineering  practice 
is  largely  concerned  with  the  harnessing  of  various 
forms  of  energy.  Looking  about  us  in  nature  and  in 
modern  engineering  accomplishment,  we  may  see  nu- 
merous instances  of  energy.  The  steam  engine  and 
steam  turbine  indicate  a  form  of  mechanical  energy; 
the  incandescent  light,  or  the  dynamo,  that  of  electrical 
energy;  the  evolving  of  heat  in  the  burning  of  crude 
oil,  that  of  chemical  energy ;  the  human  conducting 
of  affairs,  that  of  human  energy ;  the  rays  of  light  from 
the  sun,  dissipating  eternally  10,000  h.p.  over  each  acre 
of  the  earth's  surface,  that  of  solar  energy,  and  so  on 
indefinitely.  Modern  investigation  has  conclusively 
established  the  fact  that  all  types  of  energy  are  inter- 
changeable, and  though  some  types  of  energy  are  more 
readily  convertible  into  other  types,  yet  the  basic  law 
is  true  that  no  energy  in  sum  total  is  ever  destroyed, 
and  on  this  basis,  or  law,  known  as  conservation  of  en- 
ergy, practically  all  of  our  engineering  formulas  and 
computations  are  evolved. 

The  conversion  of  the  chemical  energy  of  crude 
oil  into  heat  energy  of  the  furnace  and  thence  into 


22  FUEL  OIL  AND  STEAM  ENGINEERING 

steam  largely  concerns  our  attention  in  this  discussion. 
Thus  each  pound  of  California  crude  oil  will  be  found 
in  later  articles  to  contain  approximately  18,500  Brit- 
ish thermal  units  of  heat  energy.  This  energy  of  one 
pound  of  oil  when  wholly  converted  into  mechanical 
energy*  is  sufficient  to  lift  a  person  weighing  150 
pounds  through  a  vertical  skyward  journey  of  some  18 
miles.  Hence  the  study  of  the  application  of  such 
enormous  reservoirs  of  energy,  latent  in  crude  pe- 
troleum, will  prove  intensely  interesting  and  in- 
structive. 


The   Safety  Valve   Shows   the  Possibility   of   Safety 
Application,  when  Pressures  Become  Unbalanced 

Bearing  in  mind  these  fundamental  laws,  we 
should  now  be  able  to  see  mentally  the  exact  changes 
of  energy  that  are  going  on  in  the  modern  power  plant ; 
first  as  chemical  energy  in  oil,  next  as  latent  heat 
energy  in  furnace  gases,  then  as  latent  heat  energy  in 
steam,  next  as  energy  of  motion  in  the  moving  parts 
of  the  powder  generating  apparatus,  where  the  final 
transformation  into  electrical  energy  is  brought  about. 


CHAPTER  III 


THEORY  OF  PRESSURES 

N  the  preceding  discus- 
sions we  have  seen  that 
a  force  is  said  to  be  act- 
ing whenever  the  phys- 
ical conditions  are  such 
that  the  velocity  of  a 
body  tends  to  be  changed 
in  magnitude  or  direc- 
tion. If  two  opposing 
forces  are  equally  bal- 
anced, there  is  simply  a 
tendency  to  change  mo- 
tion and  such  a  force  is 
known  as  a  pressure. 
This  opposing  force  in 
the  case  of  a  gas  or  vapor 
under  pressure  is  sup- 
plied by  the  walls  of  the 

containing  vessel.     Pressures  then  constitute  an  im- 
portant  phase   of   steam   engineering   practice. 

The  Steam  Gage. — In  steam  engineering  practice 
heavy  pressures,  that  is  pressures  above  the  atmos- 
phere, are  usually  measured  by  means  of  an  instru- 
ment known  as  a  steam  gage.  This  gage  consists  of  a 
piece  of  hollow  metal  bent  into  a  circular  shape  which, 
under  pressure,  tends  to  straighten  out.  This  straight- 
ening effect  is  proportional  to  the  pressure  under 
which  the  boiler  is  working.  A  rack  and  pinion  move- 
ment, placed  on  the  end  of  this  curved  piece  of  metal 
in  the  steam  gage,  causes  the  needle  of  the  gage  to 
indicate  pressure  readings.  By  comparing  this  gage 
with  a  definite  standard  its  accuracy  is  ascertained. 

23 


The    Thermometer    Suspension 
for   Barometer    Correction 


24 


FUEL  OIL  AND  STEAM  ENGINEERING 


The  Difference  Between  Absolute  Pressure  and 
Gage  Pressure.  —  There  is  a  point  at  which  a  gas  is 
said  to  exert  no  pressure.  This  expanded  condition 
of  a  gas  has  never  been  wholly  realized  in  practice,  yet 
this  very  beginning  point  or  zero  value  is  most  con- 
venient in  expressing  pressure  valuations  and  such 
denotations  are  known  as  absolute  pressure  values. 
The  steam  gage  attached  to  the  boiler  does  not  read 
absolute  pressure  values,  but  such  pressure  readings 
are  known  as  pounds  pressure  per  sq.  in.  (gage)  which 
means  that  one  must  add  the  absolute  pressure  of  the 
atmosphere,  Pa,  to  the  gage  reading,  Pg,  in  order  to 
ascertain  the  true  absolute  pressure  P  under  which  the 
boiler  is  generating  steam.  Thus 


Thus,  if  a  pressure  gage  of  the  steam  boiler  reads 
186.4  Ib.  per  sq.  in.  and  the  pressure  of  the  atmosphere 
is  found  to  be  14.6  Ib.  per  sq.  in.,  the  absolute  pressure 
under  which  the  boiler  is  operating  is 

P  =  186.4+  14.6  =  201.0  Ib.  per  sq.  in. 

The  Column  of  Mercury.  —  The  most  accurate 
method  of  measuring  small  pressures  such  as  the  pres- 
sure of  the  atmosphere  and  condenser  vacuum  pres- 
sure is  by  means  of  a  vertical  column  of  mercury. 


7 

h 


The    Principle   of   the   Atmospheric    Barometer,    the 

Condenser  Vacuum  and  the  Measurement  of 

Pressures  above  the  Atmosphere 

In  its  simplest  form  this  consists  of  a  long  glass  tube 
closed  at  one  end  and  filled  with  mercury.  The  tube 
is  then  inverted  and  the  open  end  placed  in  a  vessel 
of  mercury  exposed  to  the  atmosphere  or  condenser 
as  the  case  may  be,  as  shown  in  the  illustration. 


THEORY  OF  PRESSURES 


25 


In  the  case  of  atmospheric  pressure  determination 
the  mercury  will  at  once  lower  itself  in  the  long  tube 
until  the  height  of  enclosed  mercury  above  that  in  the 
vessel  is  sufficient  to  balance  the  pressure  from  the 
atmosphere  without.  If  the  barometer  be  at  sea-level 
and  the  temperature  of  the  mercury  column  32°  F., 
the  height  of  mercury  will  now  measure  exactly  29.921 
inches  for  such  standard  conditions. 

Vacuum  Pressures. — It  has  already  been  pointed 
out  that  measurement  of  pressure  by  means  of  the 


Interior    and    Exterior    View    of    Steam    Gage,    showing    Principle 
of  Operation 

steam  gage  indicates  a  pressure  over  and  above  that 
exerted  by  the  atmosphere  and  consequently  to  ascer- 
tain the  true  absolute  pressure  of  the  fluid  under  meas- 
urement we  must  add  to  the  gage  reading  the  atmos- 
pheric pressure  of  the  day.  And  so  in  the  measuring 
of  the  pressure  of  a  condenser,  unavoidably  there  has 
grown  up  a  similar  but  opposite  custom  in  which  the 
pressure  is  measured  down  from  the  atmosphere.  Such 
a  reading  is  known  as  a  vacuum  pressure.  In  order 
then  to  ascertain  the  absolute  pressure  P  under  which 
a  condenser  is  operating  it  is  necessary  to  subtract 
the  vacuum  pressure  reading  Pv  from  the  atmospheric 
pressure  reading  Pa.  Thus 


26  FUEL  OIL  AND  STEAM  ENGINEERING 

P  =  Pa  —  Pv   ....  ..........................    (2) 

Thus  if  a  condenser  is  operating  under  28.5  in.  of 
vacuum  and  the  atmospheric  pressure  is  29.92  in.,  we 
mean  that  the  actual  air  and  steam  still  undisposed 
of  in  the  condenser  exert  an  absolute  pressure  equiva- 
lent to  the  difference  between  29.92  and  28.50  which  is 
1.42  in.  of  mercury. 

Confusion  in  Pressure  Units.  —  We  now  see  that 
readings  in  inches  of  mercury  for  low  pressure  and 
pounds  pressure  per  sq.  in.  for  high  pressure  are  ex- 
pressions that  are  not  at  all  comparable  to  each  other 
and  hence  their  interrelation  becomes  an  endless 
source  of  confusion. 

Relationship  of  Pressure  Units.  —  By  careful  meas- 
urement of  the  atmosphere  at  sea-level,  scientists  have 
established  that  the  height  of  a  mercury  column  with 
the  mercury  at  32°  F.  in  temperature  is  29.921  in. 
Such  a  column  of  mercury  one  square  inch  in  cross- 
section  weighs  14.696  Ib.  This  gives  us  at  once  a 
method  by  which  we  may  transfer  inches  of  mercury 
Im  into  pounds  of  pressure  per  square  inch  P.  Thus 

Im        29.921 

-  ...........  ..................   (3) 

P         14.696 

Inches  of  Water  and  Pounds  Pressure  per  Square 
Inch.  —  Very  slight  pressures  are  often  measured  in 
inches  of  water  above  or  below  atmospheric  pressures. 
Thus,  in  determining  the  draft  of  a  chimney,  a  "U" 
tube  is  inserted  into  the  chimney,  and  the  height  of 
the  unbalanced  portion  of  the  water  column  indicates 
the  draft  in  the  chimney  in  inches  of  water.  Since  a 
column  of  water  1728  in.  high  and  one  square  inch  in 
cross-section  at  100°  F.  weighs  exactly  62  Ib.,  the 
inches  of  water  Iw  may  be  converted  into  Ib.  pressure 
per  sq.  in.  P  by  the  formula 

Iw  1728 


P  62 

The  Thirty  Inch  Vacuum.  —  In  engineering  prac- 
tice a  thirty  inch  mercury  vacuum  is  considered  to  be 


THEORY  OF  PRESSURES 


27 


the  point  of  absolute  zero  in  pressure.  This  is  not 
strictly  true,  however,  for  we  have  just  seen  that  such 
an  absolute  zero  point  is  reached  under  a  vacuum  pres- 
sure of  29.921  in.  of  mer- 
cury. The  reading  of 
the  column  of  mercury 
in  this  case  is  taken 
when  the  mercury  is  at 
a  temperature  of  32°  F., 
which  is  the  standard 
temperature  for  scien- 
tific measurement.  If, 
however,  we  change  our 
standard  to  that  of  58.4° 
F.  the  same  weight  or 
pressure  of  mercury  now 
measures  just  30.0  in. 
This  temperature  is 
more  nearly  that  of  the 
condenser  room  where 
atmospheric  pressures 
are  read  and  since  it 
makes  a  column  of  even 
thirty  inches  in  height, 
we  shall  adopt  such  a 
reading  at  58.4°  F.  as 
standard  for  absolute 
vacuum  measurement.  We  shall,  however,  bear  in 
mind  that  the  same  column  at  32° F.  would  stand  at 
29.921  inches. 

The  Practical  Formula  for  Conversion  of  Pressures 
— Since  we  have  thus  established  an  even  unit  for  the 
standard  vacuum,  we  may  also  consider  14.7  pounds 
pressure  per  square  inch  as  its  equivalent  instead  of 
the  cumbersome  figure  of  14.696  as  stated  above.  This 
involves  an  error  of  four  points  in  fifteen  thousand 
which  is  negligible.  Our  formula  for  reduction  on  the 
thirty  inch  vacuum  becomes 

Im  30 

-'.. (5) 

P  14.7 


Typical  Condenser  Barometer  for 
Steam  Turbine  Operation 


28  FUEL  OIL  AND  STEAM  ENGINEERING 

To  Reduce  Barometer  Readings  to  the  Standard 
Thirty  Inch  Vacuum. — Although  58.4°  is  nearer  the 
condenser  room  temperature  than  is  the  32°  F.  basis, 
still  for  accurate  measurement  the  actual  temperature 
of  the  medium  surrounding  the  mercury  column 
should  be  ascertained  and  thus  a  correction  must  be 
made  to  reduce  the  height  of  the  mercury  column  to 
what  it  would  read  if  at  a  temperature  of  58.4°  F. 

This  is  best  illustrated  by  taking  a  concrete  exam- 
ple. Let  us  suppose  that  the  mercury  column  inserted 
into  the  condenser  of  a  turbine  reads  28.56  in.  when 
the  mercury  temperature  is  82°  F.  and  that  a  barom- 
eter in  the  vicinity  indicates  the  atmospheric  pressure 
in  the  condenser  room  to  be  30.08  in.  of  mercury 
when  its  mercury  column  is  at  78°  F. 

The  first  thing  to  be  done  in  the  solution  of  this 
problem  is  to  ascertain  what  the  two  mercury  col- 
umns would  have  read  had  their  respective  mercury 
columns  been  at  58.4°  F.  Scientific  investigation  indi- 
cates that  the  expansion  of  mercury  is  according  to 
the  following  equation  in  which  It  is  the  height  in 
inches  of  mercury  at  t°  F.  and  Im  at  58.4°  F. 

It  =  Im  [1.0026  +  .000104  (t  —  58.4)  ]    (6) 

Hence,  to  ascertain  the  true  vacuum  reading  in  inches 
of  mercury  we  find  by  substitution 

28.56  —  Im  [1.0026  +  .000104  (82  —  58.4)  ] 
.Mm  =  28.415. 

Similarly  to  compute  the  corrected  barometer 
reading  of  the  day,  we  find  by  substitution  that 

30.08  =  Im  [1.0026  +  .000104  (78  —  58.4)  ] 
.Mm  =  29.942. 

The  net  absolute  pressure  will  now  be  the  differ- 
ence between  the  corrected  atmospheric  barometer 
reading  and  the  corrected  vacuum  reading  for  the 
condenser,  which  according  to  equation  (2)  is 

IP  =  29.942  —  28.415  =  1.527  in.  of  mercury. 
Since  all  standard  vacuums  in  engineering  prac- 
tice are  now  measured  on  a  30  inch  vacuum  basis,  we 


THEORY  OF  PRESSURES  29 

find  that  the  corrected  vacuum  reading  Icv  for  a  con- 
denser is 

lev  =  30—  Ip  ..............................    (7) 

.Mcv  =  30—  1.527  =  28.473  in.  (vacuum). 

This  corrected  vacuum  reading  Icv  which  in  this 
case  is  28.473  is  commonly  spoken  of  as  the  vacuum 
referred  to  a  30  inch  barometer. 

For  delicate  scientific  work  this  reading  should 
be  carried  to  still  further  refinements  by  making  a  cor- 
rection for  the  expansion  of  the  brass  on  the  barom- 
eter scale  and  also  for  a  variation  in  gravity  at  the 
particular  place  of  measurement.  At  high  altitudes 
and  extreme  northern  and  southern  latitudes  such  a 
correction  is  essential. 

Corrections  for  the  Brass  Scale  of  a  Barometer.  — 

Professor  Marks  in  his  computation  of  steam  tables  for 
condenser  work  published  by  the 
Wheeler  Condenser  and  Engi- 
neering Company  has  ably  dis- 
cussed the  correction  for  relative 
expansion  of  mercury  and  the 
brass  scale  of  the  barometer  as 
follows  : 

The  linear  expansion  of  brass 
is  about  one-tenth  that  of  the  ap- 
parent linear  expansion  of  mer- 
cury exerting  a  constant  pressure. 
Where  a  mercury  column  has  a 

A  hand  Adjuster  brass   scale   extending   its   whole 


'  height   which   is   free   to    expand 


with  changes  in  temperature,  the 

readings  on  the  brass  scale  of  the  height  of  the  mercury 
column  must  be  corrected  for  the  relative  expansion 
of  the  mercury  and  the  brass  scale.  The  following 
table  is  taken  from  table  99  of  the  Smithsonian  phys- 
ical tables  and  gives  the  constants  for  various  barom- 
eter heights  by  which  to  multiply  the  temperature 
correction  in  order  to  obtain  the  corrections  of  the 
mercury  column. 


30 


FUEL  OIL  AND  STEAM  ENGINEERING 


Reduction  of  Barometric  Height  to  Standard 

Temperature  Cor  • 

rections  for 

Relative  Expansion 

of  Mercury 

and  Brass  Scale. 

Height  of 

Correction 

Height  of 

Correction 

Barometer 

in  inches  per 

Barometer 

in  inches  per 

in  inches. 

deg.  F. 

in.  inches. 

deg.  F. 

20.0 

O.iOOlSl 

28.0 

0.00254 

20.5 

.00185 

28.5 

.00258 

21.0 

.0(0190 

29.0 

.00263 

21.5 

.00194 

29.2 

.00265 

22..0 

.00199 

29.4 

.00267 

22.5 

.00203 

29.6 

.00268 

23.0 

.00208 

29.8 

.00270 

23.5 

.•00212 

30.0 

.00272 

24.0 

0.00217 

30.2 

0.00274 

24.5 

.00221 

3.0.4 

.00276 

25.0 

.00226 

30.6 

.00277 

25.5 

.00231 

30.8 

.00279 

26.0 

.00236 

31.0 

.00281 

26.5 

.00240 

31.2 

.00283 

27.0 

.00245 

31.4 

.00285 

27.5 

.00249 

31.6 

.00287 

Example:  Reading  of  barometer  29.84,  tempera- 
ture of  barometer  77°  F.  In  the  foregoing  table  the 
nearest  figure  to  29.84  is  29.8  opposite  which  the  cor- 
rection factor  is  .0027.  If  it  is  desired  to  reduce  the 
barometer  to  a  58.4°  F.  standard,  the  change  in  tern- 


Five  Outlets  for  Measuring  Chimney  Draft  Pressures 
with  One  Draft  Gage 


THEORY  OF  PRESSURES  31 

perature  is  from  79°  to  58.4°  =  20.6°  and  multiplying 
.0027  by  20.6  we  get  .056  inches  as  the  barometer  cor- 
rection. Subtracting  this  from  29.84  in.  we  get  the 
barometer  reading  for  mercury  at  58.4°  F.  as  29.84  in. 
—  .056  in.  =  29.784  in. 

Corrections  for  Altitude  and  Latitude.  —  Since  the 
height  of  a  mercury  column  gives  true  pressure  read- 
ings so  long  as  it  represents  a  definite  force  or  weight 
and  since  the  weight  or  force  of  gravity  varies  at  dif- 
ferent altitudes  and  latitudes  over  the  earth's  surface, 
it  is  necessary  to  enter  such  a  correction  when  the 
extreme  refinements  of  the  work  in  hand  demand  it. 
The  standard  value  of  gravity  is  taken  at  32.173.  The 
following  formula,  in  which  Img  is  the  correct  reading, 
g  is  the  gravity  coefficient,  A  the  latitude,  and  h  the 
altitude  at  the  point  of  pressure  measurement,  may  be 
applied  for  this  correction. 

32.173  —  .082  Cos2A  —  .000003  h 

Img=[-  -]     Im..-.     (8) 

32.173 

Thus  in  a  certain  engineering  investigation  in 
Berkeley,  California,  where  the  latitude  is  38°  and  the 
elevation  50  ft.,  the  condenser  mercury  column  cor- 
rected for  temperature  read  28.473  in.  What  should 
its  properly  corrected  reading  be  when  gravity  is  taken 
into  consideration? 

By  substitution 

32.173  —  .082  X  -2419  —  .00015 
Img  =  -  -X  28.745 

32.173 

32.153 

-  X  28.473  =  28.464. 


32.173 

Such  refinements  as  the  one  for  brass  scale  cor- 
rection and  especially  for  latitude  and  altitude  read- 
justments are  not  necessary  in  most  steam  engineer- 
ing tests.  It  is  well,  however,  to  bear  in  mind  such 
computation  in  case  investigations  of  extreme  detail 
should  arise. 


CHAPTER  IV 

MEASUREMENT  OF  TEMPERATURES 


HEN  the  finger  is  inserted 
into  a  cup  of  warm  water 
and  then  again  into  water 
formed  by  the  melting  of 
ice  a  distinct  sensation  is 
felt  in  each  case.  Many 
years  ago  scientists  and 
philosophers  attempted  to 
explain  this  sensation  by 
assuming  that  a  substance 
existed  which  they  called 
"caloric"  whose  entrance 
into  our  bodies  caused  the 
sensation  of  warmth  and 
whose  egress  therefrom 
gave  the  sensation  of  cold. 
But  heat,  if  a  substance  at 
all,  cannot  be  similar  to 

t  h  substances      With 

.  . 

which  we  are  familiar, 
since  a  hot  body  weighs  no  more  than  one  which  is 
cold. 

The  discussion  in  this  article  is  not  concerned 
directly  with  heat  but  rather  with  one  of  its 
effects,  namely,  that  of  change  in  temperature. 
From  the  above  it  is  readily  seen  that  temperature 
is  an  indicator  of  the  physical  effect  of  heat  rather 
than  a  quantitative  means  of  heat  measurement.  This 
statement  is  easily  proved,  for  when  we  place  our 
fingers  alternately  upon  a  piece  of  cold  and  hot 
^f  on  at  the  temperatures  mentioned  for  water  in  the 

32 


A  Thermocouple  for  High  Tern- 
perature  Measurement 


MEASUREMENT  OF  TEMPERATURES        33 

opening  paragraph  of  this  discussion,  the  same  phys- 
ical sensation  is  experienced.  Yet  to  transform  the 
iron  from  a  temperature  ot  freezing  water  to  that  of 
boiling  water  takes  far  less  heat  than  for  the  trans- 
fer of  water  under  similar  conditions. 

Fixed  Points  for  Thermometer  Calibration. — Since 
water  is  the  most  generally  distributed  substance 
throughout  nature  and  one  of  the  most  convenient 
for  handling  in  the  laboratory  its  freezing  point  and 
boiling  point  are  used  by  common  consent  as  two 
definite  marks  for  temperature  calibration.  Thus  in 
the  Centigrade  scale  the  freezing  point  of  water  .is  the 
zero  point  and  the  boiling  point  of  water  under  stand- 
ard conditions  of  atmospheric  pressure  is  the  one 
hundred  unit  point.  Again,  in  the  Fahrenheit  scale 
the  freezing  point  of  water  is  the  thirty-second  division 
point  and  the  boiling  point  of  water  the  two  hundred 
and  twelfth  division  point.  Similarly  for  the  Reaumur 
scale,  the  freezing  point  of  water  is  the  zero  division 
point  and  the  boiling  point  of  water,  the  eightieth 
division  point. 

The  Various  Temperature.  Scales  Employed. — The 
Centigrade  scale  as  described  above  has  grown  into 
rapid  use  in  scientific  investigation  and  now  may  be 
said  to  be  universally  adopted  throughout  the  world 
for  such  practice.  The  Fahrenheit  scale,  on  the  other 
hand,  has  so  ingrained  itself  into  engineering  practice 
that  engineers  are  loath  to  part  with  it  in  spite  or 
its  cumbersome  and  unscientific  divisions.  In  this 
work,  then,  we  shall  be  compelled  to  express  temper- 
ature measurement  in  the  Fahrenheit  scale.  The 
Reaumer  scale,  mentioned  above,  finds  slight  applica- 
tion in  this  country  and  in  such  places  where  it  is 
employed  it  is  used  for  measurement  in  stills  and 
breweries.  All  three  of  these  scales  are  often  for 
scientific  purposes  transformed  to  a  socalled  absolute 
zero  which  is  459.4°!  yF.  below  the  ordinary  zero 
on  the  Fahrenheit  scale.  A  free  discussion  of  this 
absolute  scale  will  be  set  forth  in  a  discussion  on 


34 


FUEL  OIL  AND  STEAM  ENGINEERING 


thermodynamic  laws  of  gases  which  will  be  found  in 
another  chapter. 

Relationship  of  Fahrenheit  and  Centigrade  Values. 

In  order  that  transfers  from  one  thermometer  scale 
to  another  may  be  conveniently  and  rapidly  accom- 
plished, it  now  becomes  necessary  to  develop  some 
simple  mathematical  relationships  whereby  this  may 
be  done.  Since  all  of  the  scales  are  graduated  uni- 
formly between  the  freezing  and  boiling  point  of  water, 
their  relationship  may  be  said  to  be  linear.  In  the 
study  of  analytical  geometry  we  find  that  such  rela- 
tionships may  be  expressed  by  the  straight  line 
formula : 


y  — 


X9 X, 


(i) 


The  Linear  Relationship  of  Temperature  Scales 

wherein  x  and  y  represent  any  simultaneous  tempera- 
tures expressed  in  different  scale  readings  and  the 
subscripts  1  and  2  represent  definitely  known  points  in 
correspondence.  In  order  then  to  find  a  relationship 
between  the  Fahrenheit  and  Centigrade  scale,  if  x  rep- 
resents the  Fahrenheit  and  y  the  Centigrade,  we  find 
that  Xj  would  be  32  when  y±  is  0,  and  x2  would  be  212 
when  y2  is  100.  Consequently  we  derive  a  relationship 
thus: 


MEASUREMENT  OF  TEMPERATURES        35 

F  — 32  C  — 0 


212—32  100  —  0 

180 
F  — 32  = C 


100 
9 
.-.  F  — 32  =  — C (2) 

5 

As  an  example,  if  the  entering  water  in  a  boiler 
test  is  84°  F.,  this  value  is  converted  at  once  to  the 
Centigrade  scale  by  substituting  in  the  formula 

9 
F  — 32  =  — C 

5 

5  5 

or  C  =  —  (F  —  32)  =  —  (84  —  32)  =  28.9° 
9  9 

Relationship  of  Fahrenheit  and  Reaumur  Values. 
A  relationship  between  the  Fahrenheit  and  Reaumur 
scales  is  similarly  established. 

9 
/.F  — 32  =  — R ' (3) 

4 

Thus  in  order  to  illustrate  the  application  of  this 
formula  a  temperature  of  84°  F.  reduces  to  the  Reau- 
mur scale  as  follows : 

9 
84  —  32  =  —  R 

4 

.-.  R  =  23.1° 

Relationship  of  Centigrade  and  Reaumur  Values. 
To  develop  a  relationship  between  the  Centigrade  and 
Reaumur  scales  the  same  reasoning  is  involved. 

5 
/.C  =  —  R   (4) 

4 


36  FUEL  OIL  AND  STEAM  ENGINEERING 

Thus  to  convert  a  Centigrade  reading  of  28.9° 
into  the  Reaumur  scale,  we  substitute  directly 

4 
R  =  — C 

5 

.      4 
or  R  =  —X  28.9  =  23.1° 

5 

In  case  that  rapidity  is  necessary  in  the  conversion 
of  one  scale  to  another  and  extreme  accuracy  is  not 
required,  a  conversion  chart  is  easily  constructed 
whereby  these  three  scales  may  be  converted  graph- 
ically from  one  to  the  other. 

Methods     of     Temperature     Measurement.     The 

ascertaining  of  correct  temperatures  is  of  ex- 
treme importance.  Due  to  the  wide  range  of  tem- 
peratures that  occur  in  practice,  a  number  of  different 
methods  of  temperature  measurement  are  necessary. 
The  method  to  be  employed  depends  upon  the  range 
of  temperature  involved  and  often  too  upon  the  access- 
ibility of  the  object  whose  temperature  is  desired. 
We  shall  describe  first  the  approximate  methods  that 
are  used  in  the  ascertaining  of  temperatures. 

Estimation  by  Flame  Color. — A  number  of  years 
ago  in  the  steel  industry,  it  was  found  that  a  flame 
emitted  definite  gradations  of  color  depending  upon 
its  temperature.  In  1905  the  Bureau  of  Standards 
issued  a  bulletin  covering  this  point  and  made  a  state- 
ment that  one  may  ascertain  temperatures  with  an 
accuracy  of  100  to  150°  F.  by  means  of  eye  judgment. 
It  is  stated,  however,  that  it  is  impossible  to  ascertain 
temperatures  above  2200°  F.  As  this  is  the  upper 
limit  of  furnace  heating  in  steam  engineering,  we 
need  not  then  be  concerned  with  exceeding  the  limit. 

In  a  booklet  published  by  the  Halcomb  Steel 
Company,  1908,  the  following  tabulation  is  given  t(/ 
aid  eye  judgment  in  estimating  temperatures: 


MEASUREMENT  OF  TEMPERATURES 


37 


°c. 

op 

Colors.                                             °C.         °F. 

Colors. 

400 

752 

Red, 

visible 

in 

the 

dark  

1000 

1832 

Bright  cherry-red 

474 

885 

Red, 

visible 

in 

the 

twilight  .  . 

1100 

2012 

Orange-red. 

525 

975 

Red, 

visible 

in 

the 

day-light  . 

1200 

2192 

Orange-yellow. 

581 

1077 

Red, 

visible 

in 

the 

sunlight  . 

1300 

2372 

Yellow-white. 

700 

1292 

Dark 

red 

1400 

2552 

White  welding  heat 

son 

1472 

Dull 

,              , 

1500 

2732 

Brilliant  white. 

oUU 

900 

1652 

1600 

2912 

Dazzling   white 

y 

(bluish  white). 

The  Melting  Point  of  Metals  and  Alloys. — Another 
method  of  approximately  ascertain- 
ing the  temperature  is  by  means  of 
the  melting  points  of  alloys  and 
metals.  A  number  of  these  alloys 
are  on  the  market  and  are  con- 
venient in  ascertaining  the  approxi- 
mate temperature  of  furnaces  and 
other  heat  generating  apparatus. 

The   Method  of   Immersion. — A 

third  method  is  by  heating  a  piece 
of  metal  of  known  weight  and  spe- 
cific heat  to  the  temperature  of  the 
furnace  and  then  immersing  the 
heated  body  in  water.  By  knowing 
the  rise  in  temperature  of  the  water,  the  tempera- 
ture of  the  furnace  may  be  approximately  ascertained. 
The  loss  of  heat  in  the  hot  substance  is  evidently 
equal  to  the  heat  gained  by  the  water.  Let  tx  be  the 
unknown  temperature  of  the  hot  substance,  Mx  the 
weight  of  the  hot  substance  in  lb.,  Mw  the  weight 
of  the  water  in  lb.,  t2  the  final  temperature  of  the 
water,  tx  the  initial  temperature  of  water,  and  cx  the 
specific  heat  of  the  hot  substance ;  then,  if  we  assume 
that  the  specific  heat  of  the  water  is  1,  we  may  write 
at  once 


A  Cup  for  Melting 
Alloys 


Mx  (tx  — 12)  cx  =  Mw  (t2  — 1± 

Mw(t2-ta) 
Therefore,    tx  =  -  f-  t2 


(5) 


Mxcx 


Mean  specific  heats  of  a  number  of  metals  which 
may  be  used  for  this  purpose  are  as  follows : 


38 


FUEL  OIL  AND  STEAM  ENGINEERING 


The 


Mean  Specific  Heats. 

Ordinary  Mean  for  High 

Substance.                                      Temperature.  Temperature. 

Platinum     ...................  032  .038 

Iron    (cast)     .................  130  .180 

Nickel     .....................  109  .136 

As  an  example  let  us  suppose  that  4  Ib.  of  cast 
iron  heated  to  an  unknown  temperature  is  plunged 
into  20  Ib.  of  water  at  64°  F.,  thereby  raising  the 
water  to  a  temperature  of  124°  F.  By  substituting 
in  the  formula,  we  have 

20(124  —  64) 

tx  =  -  -+124=  1791°  F. 

4X-180 

Alcohol    and    Mercurial    Thermometers.  — 

For  accurate  temperature  readings 
up  to  900°  F.  the  expansion  of 
liquids  is  made  use  of,  for  experi- 
ment shows  that  the  expansion  of 
a  liquid  is  proportional  to  the  rise 
of  temperature.  Since  alcohol  has 
a  low  freezing  point,  in  fact  so  low 
that  it  cannot  be  reached  by  any 
natural  temperature,  the  alcohol 
thermometer  is  usually  made  use  of 
for  low  temperature  readings.  Since 
its  boiling  point  is  also  compara- 
tively low,  it  is  impracticable  for 
high  temperatures.  Mercury,  on  the 
other  hand,  is  an  excellent  substance 
to  use  in  thermometers  as  the  varia- 
tion in  its  expansion  coefficient 
with  rise  of  temperature  is  such 
that'  the  deleterious  effect  of  the 
expansion  coefficient  in  the  glass 
tube  is  very  nearly  offset  by  the 
compensating  error  introduced  by 
assuming  a  constant  expansion  coefficient  for  the 
mercury.  Mercury  boils  at  676°  F.  and  for  many  de- 
grees below  this  point  gives  off  considerable  vapor. 
As  a  consequence  the  ordinary  mercurial  thermometer 


Hygrometer    for 

Boiler   Room 

Humidity 


MEASUREMENT  OF  TEMPERATURES 


39 


cannot  be  depended  upon  for  a  higher  temperature 
than  500°  F.  An  ingenious  device,  however,  enables 
us  to  make  use  of  the  mercurial  thermometer  up  to 
800  or  900°  F.  A  small  amount  of  nitrogen  gas  is 
put  in  the  upper  column  of  the  thermometer  tube 
and  as  the  mercurial  column  expands  it  consequently 
compresses  the  nitrogen  gas.  The  reactive  pressure 
of  the  gas  upon  the  mercury  raises  its  boiling  point 
so  that  the  high  temperatures  above  indicated  can 
be  accurately  read. 

The  Expansion  Pyrometer. — For  the  estimating 
of  temperatures  higher  than  900°  a  number  of  types 
of  instruments  are  employed.  The  expansion  py- 
rometer, which  acts  upon  the  principle  that  the  ex- 
pansion of  metals  is  proportional  to  the  rise  in  tem- 
perature may  be  quite  accurately  used  between  the 
range  of  1200  to  1500°  F. 

Electrical    Thermometers.  -  -  Electrical    thermo- 

i    meters  are,   however,   the 

most  satisfactory  and  ac- 
curate for  steam  engineer- 
ing practice.  Electrical 
thermometers  act  upon 
two  distinct  physical  prin- 
ciples. One  class  operates 
upon  the  principle  that 
the  junction  point  of  two 
metals  when  heated  gen- 
erates an  electromotive 
force  which  is  propor- 
tional to  the  temperature 
rise.  Consequently  if  the 
readings  are  made  by 
means  of  a  delicate  gal- 
vanometer, calibrated  to 
read  degrees  Fahrenheit, 
an  accurate  type  of  instru- 
ment is  at  once  evolved, 
based  upon  the  experi- 


Thermo- couple  Ready  for  In- 
sertion in  the  Furnace 

The     other     principle     is 


mental  fact  that  the  resistance  of  a  metal  varies  with 


40 


FUEL  OIL  AND  STEAM  ENGINEERING 


the  temperature  rise. .  Hence,  by  measuring  this  rise  in 
electrical  resistance  by  delicately  calibrated  instru- 
ments, an  accurate  thermometer  results.  The  thermo- 

Pyrometer 


Principle   of   Operation   of   the   Thermo-couple 

couples  made  use  of  for  the  former  type  of  electrical 
.  thermometer  usually  consist  of  platinum  with  plati- 
num alloyed  with  10  per  cent  of  rhodium.  In  the  lat- 
ter class  the  resistance  element  is  enclosed  in  a  highly 
refractory  substance. 

The  Radiation  Pyrometer. — Where  temperatures 
are  above  the  limit  of  measurement  by  rare  metal 
pyrometers,  or  where  the  point  of  high  temperature 
is  inaccessible  to  the  thermo-couple,  the  radiation 
pyrometer  is  employed.  This  instrument  is  focused 
on  the  hot  body  at  a  distance.  The  heat  radiating 
from  the  object  under  investigation  is  reflected  by 
a  concave  mirror  in  the  back  of  the  pyrometer  tele- 
scope and  concentrated  at  a  focus  point  on  a  small 
thermo-couple.  This  thermo-couple  gives  off  elec- 
trical energy  proportional  to  the  temperature  of  the 
radiating  body,  and  as  a  consequence  the  temperature 
is  thus  ascertained. 

Thus,  the  whole  range  of  temperatures  met  with 
in  engineering  practice  is  covered  by  some  form  of 
accurate  temperature  indicating  device.  The  Bureau 
of  Standards  at  Washington  is  ready  to  calibrate  for 
a  small  fee  any  thermometer  sent  to  them.  At  least 


MEASUREMENT  OF  TEMPERATURES 


41 


one  carefully  calibrated  thermometer  should  be  kept 
for  reference  or  comparison  in  the  laboratory  of  any 
one  interested  in  steam  engineering  testing. 

Standardization   and   Testing    of   Thermometers. 

The  testing  of  thermometers  is  of  utmost  im- 
portance. All  thermometers  should  be  carefully  cali- 
brated for  refined  steam  engineering  tests.  The 
Bureau  of  Standards  has  issued  in.  its  circular  No.  8, 
an  excellent  guide  for  such  work.  All  thermometers 
are  calibrated  when  completely  immersed  in  the  sub- 
stance whose  temperature  is  being  ascertained. 

The  Stem  Correction. — In  engineering  practice 
temperatures  of  steam  and  water  are 
usually  ascertained  by  setting  the 
thermometer  into  a  well  which  is 
sunk  into  the  pipe  conveying  the 
steam  or  water.  This  well  is  filled 
with  mercury  or  oil  and  the  heat 
transferred  to  the  thermometer  by 
conduction.  As  a  consequence,  how- 
ever, a  portion  of  the  thermometer 
protrudes  in  the  atmosphere  above 
the  well  and  is  consequently  at  a 
lower  temperature.  A  so-called  stem 
correction  is  hence  necessary  to  as- 
certain the  correct  reading  of  the 
thermometer. 

This  correction  is  large  if  the  number  of  degrees 
emergent  and  the  difference  of  temperature  between 
the  bath  and  the  space  above  it  are  large.  It  may 
amount  to  more  than  35°  F.  for  measurements  made 
with  a  mercurial  thermometer  at  750°  F. 

The  stem  correction  may  be  computed  from  the 
following  formula : 

Stem  correction  =  K  n(t2  —  tj (6) 

K  =  factor  for  relative  expansion  of  mercury  in  glass ; 

0.00015  to  0.00016  for  Centigrade  thermometers; 

0.000083  to  0.000089  for  Fahrenheit  thermometers  , 

at  ordinary  temperatures,  depending  upon  the 

glass  of  which  the  stem  is  made. 


Well  for 

Thermometer 

Insertion 


FUEL  OIL  AND  STEAM  ENGINEERING 

number  of  degrees  emergent  from  the  bath. 

temperature  of  the  bath. 

mean  temperature  of  the  emergent  stem. 


Galvanometer  for  Delicate  Temperature  Measurement 

Thus  suppose  that  the  observed  temperature  was 
100°  C.  and  the  thermometer  was  immersed  to  the  20° 
mark  on  the  scale,  so  that  80°  of  the  mercury  column 
projected  out  into  the  air  and  the  mean  temperature 
of  the  emergent  column  was  found  to  be  25°  C.,  then 

Stem  Correction  =  0.00015  X  80  X  (100  —  25°) 
-=  0.9°. 

As  the  stem  was  at  a  lower  temperature  than 
the  bulb,  the  thermometer  read  too  low,  so  that  this 
correction  must  be  added  to  the  observed  reading  to 
find  the  reading  corresponding  to  total  immersion. 


CHAPTER  V 


THE  ELEMENTARY  LAWS  OF  THERMO- 
DYNAMICS 

S  pointed  out  in  the  dis- 
cussion on  temperatures, 
scientists  in  former  times 
conceived  that  the  phe- 
nomena accompanying  the 
addition  or  subtraction  of 
heat  could  only  be  ex- 
plained by  the  existence 
of  a  fluid  which  they  called 
"caloric." 

But  these  scientists  or 
calorists,  as  they  were 
called,  had  to  give  a  hith- 
erto unknown  property  to 
their  substance  and  main- 
tained that  "caloric"  was  a 
weightless  fluid.  This 
substance  also  had  the  property  of  rilling  the  inter- 
stices of  bodies  and  of  passing  between  bodies  over 
any  intervening  space.  To  illustrate,  they  said, 
"caloric"  would  'fill  the  interstices  of  a  body  as  water 
enters  a  sponge.  Now,  when  we  squeeze  a  sponge 
some  of  the  water  oozes  out  and  wets  our  hands.  The 
calorists  assumed  that  the  friction  or  rubbing  of  a  body 
with  the  hand  for  instance,  made  the  hand  warm  be- 
cause friction  was  supposed  to  decrease  the  capacity 
of  a  body  for  holding  "caloric,"  and  as  in  the  squeez- 
ing of  the  sponge,  water  oozes  out,  so  caloric  oozed 
out  and  made  the  hand  feel  warm. 

The   Irrefutable     Experiments   of    Davy. — Davy, 
however,  exploded  this  theory  in  1799,  when  by  rub- 

43 


The   Establishment 
of  Boyle's   Law 


44 


FUEL  OIL  AND  STEAM  ENGINEERING 


bing  two  pieces  of  ice  together,  he  actually  caused 
the  ice  to  melt.  This  evidently  would  be  impossible 
under  the  caloric  theory  above  stated,  according  to 
which  friction  caused  capacity  for  caloric  to  be  de- 
creased. Yet  here  was  evidenced  the  adverse.  From 


The  Furnace  Gases  and  Entering-  Air  Obey  Rigid  but  Simple 
Thermodynamic  Laws.  (Boiler  Fronts  at  .Long  Beach  Plant  of 
the  Southern  California  Edison  Company.) 


time  immemorial,  men  have  considered  that  the  force 
of  truth  is  almighty,  and  yet  how  slow  the  human  race 
is  to  overthrow  an  imperfect  but  well-established  the- 
ory. For  instance,  so  powerful  was  Sir  Isaac  Newton's 
grip  on  the  scientific  world  that  because  he  announced 
that  no  successful  correction  could  ever  be  made  for 
the  uneven  refraction  of  light  rays  in  lenses,  the  whole 
world  for  fifty  years  thoroughly  abandoned  the  idea 
of  ever  being  able  to  use  refractive  telescopes,  and  con- 
sequently, during  that  period  we  find  telescopic  re- 
flective mirrors  used  entirely. 

Joule's  Complete  Demonstration  of  the  Mechanical 
Equivalent  of  Heat. — And  so  it  was  in  the  case  of  the 
theory  of  heat.  Notwithstanding  the  all-powerful  dem- 
onstration of  Davy  in  1799,  it  remained  for  Joule, 
nearly  .fifty  years  later  to  finally  put  forth  the  fin- 
ishing data  to  forever  overthrow  the  caloric  theory  and 


LAWS  OF  THERMODYNAMICS  45 

introduce  the  modern  idea  of  heat.  This  eminent  sci- 
entist constructed  a  machine  in  many  respects  similar 
to  an  ice-cream  freezer,  the  essential  difference  being, 
however,  that  the  machine  was  used  to  increase  the 
heat  in  the  liquid  instead  of  cooling  the  same.  Joule 
conceived  the  idea  that  heat  was  one  form  of  energy. 
Should  this  be  true,  it  should  be  mutually  convertible. 
One  of  the  easiest  methods  of  measuring  energy  is  the 
well  known  pile  driver.  Energy  is  definitely  computed 
by  weighing  the  hammer  in  pounds  and  multiplying 
this  weight  by  the  distance  in  feet  through  which  the 
weight  falls.  The  result  is  foot  pounds  energy.  By 
a  clever  contrivance  constructed  somewhat  on  this 
principle,  Joule  measured  the  amount  of  energy  ab- 
sorbed in  his  machine  and  the  consequent  rise  of  tem- 
perature in  the  liquid.  He  soon  established  the  fact 
that  a  definite  number  of  foot-pounds  of  mechanical 
energy  was  equivalent  to  a  definite  number  of  heat 
units  in  the  liquid.  This  experimental  result  is  most 
important  and  is  one  of  the  basic  principles  of  mod- 
ern engineering.  Careful  scientific  measurements  have 
proved  that  one  British  thermal  unit,  or  B.t.u.  of  heat 
energy  is  equivalent  to  777.5  foot-pounds  of  mechanical 
energy. 

The  First  Law  of  Thermodynamics. — From  this 
discussion  it  follows  that  the  first  and  greatest  law  of 
thermodynamics  is  the  mathematical  expression  of  the 
fact  that  heat  energy  and  mechanical  energy  are 
mutually  interchangeable.  Thus  if  W  represents  en- 
ergy in  foot-pounds ;  H,  energy  in  heat  units ;  and  J, 
this  experimentally  determined  constant,  we  have  the 
relationship 

W==HJ   (1) 

In  steam  engineering  practice  H  is  usually  ex- 
pressed in  B.t.u.  and  the  quantity  J  has  a  value  of  777.5 
as  has  been  stated  above.  In  other  words,  1  B.t.u. 
of  heat  energy  is  equivalent  to  777.5  ft.  Ib.  of  mechan- 
ical energy.  In  the  chapter  on  units,  we  have  defined 
the  fundamental  unit  of  energy,  namely  the  foot-pound. 
This  unit  of  heat  energy  now  introduced,  known  as  the 


46  FUEL  OIL  AND  STEAM  ENGINEERING 

British  thermal  unit  is  the  l/180th  part  of  the  heat 
necessary  to  raise  one  pound  of  water  from  32°  F.  to 
212°  F.  under  standard  atmospheric  conditions  of  pres- 
sure. This  is  the  unit  which  has  been  adopted  by 
Marks  and  Davis,  in  their  ''Steam  Tables  and  Dia- 
grams" and  although  differing  from  other  previously 
existing  units  is  nevertheless  practically  universally 
adopted  at  this  time. 

Boyle's  Law.  Early  in  the  last  century,  Boyle 
established  the  fact  that  a  perfect  gas,  such  as  air, 
follows  very  closely  the  law  known  as  Boyle's  law, 
that  the  product  of  its  pressure  and  volume  is  always 
constant  provided  the  temperature  is  kept  constant. 
Expressing  this  in  mathematical  symbols,  if  p  is  the 
absolute  pressure  in  Ib.  per  sq.  ft. ;  v,  the  volume  in 
cu.  ft.  cccupied  by  1  Ib.,  we  have  the  relationship 

p  v  =  po  v0  (2) 

Steam  is  not  a  perfect  gas  and  hence  does  not  obey 
this  law  with  exactness,  still  the  formula  may  be  used 
with  a  fair  degree  of  accuracy  when  considering  super- 
heated steam.  Accurate  formulas  will  be  given  later 
for  steam  variation.  As  an  instance,  however,  oi  ap- 
proximate computation,  let  us  consider  a  boiler  oper- 
ating at  186.3  Ib.  gage  or  201  Ib.  absolute  pressure 
per  sq.  in.,  and  producing  superheated  steam  at  527°  F. 
If  we  know  the  volume  at  one  pressure  we  may  ascer- 
tain approximately  the  volume  at  another  pressure. 
In  the  steam  tables  the  volume  of  steam  at  201  Ib. 
pressure  per  sq.  in.  is  found  to  be  2.83  cu.  ft.  per  Ib. 
Hence  at  250  Ib.  pressure  the  volume  would  become 

200  X  2.83 

v  =  —  —  —  2.26  cu.  ft.  per  Ib.  The  steam  tables 

250 

give  this  quantity  by  actual  experiment  as  2.31.  Hence 
the  formula  is  seen  to  work  with  superheated  steam 
within  2.5  per  cent  of  accuracy.  For  chimney  flue  gases 
and  air,  however,  Boyle's  law  is  very  exact. 

Charles'  Law.  In  1806  another  law  was  found 
connecting  the  variables  of  a  perfect  gas.  This  great 
law,  known  as  Charles'  Law  sets  forth  the  fact  that 


LAWS  OF  THERMODYNAMICS 


47 


when  the  pressure  is  kept  constant  the  volume  of  a 
gas  increases  proportionately  to  the  increase  in  tem- 


Superheated  Steam  Approximately  Obeys  Simple  Thermodynamic 
Laws.  (Superheated  Steam  Ducts  of  Station  C  of  the  Pacific  Gas 
&  Electric  Company  in  Oakland.) 

perature.  Thus  if  t  is  the  temperature  in  degrees 
Fahrenheit  this  law  states  that 


t  — 32 

-        - 

491.6 


(3) 


As  an  illustration,  if  we  wish  to  compute  the 
volume  that  1  Ib.  of  air  would  occupy  in  a  furnace  at 
2100°  F.,  knowing  that  v0  has  a  value  of  12.39  cu.  ft.  for 


air   at   32°    F.   then   v  =  12.39 


2100  —  32 


491.6 


'  =  69.8 


cu.  ft. 

The  Absolute  Scale.  The  establishment  of  this  law 
indicates  the  fact  that  all  temperatures  should  natur- 
ally be  measured  from  a  point  other  than  that  of  the 
freezing  temperature  of  water.  Thus  it  is  seen  from 
the  above  that  a  point  of  459.6°  below  the  ordinary 
Fahrenheit  scale  would  be  known  as  an  absolute  zero. 
Throughout  this  work  then  T  will  represent  the  abso- 
lute scale  and  t  the  ordinary  scale.  Thus 

T  =  t  +  459.6  .  ..............   (4) 


48  FUEL  OIL  AND  STEAM  ENGINEERING 

The  Composite  Law  of  Gases. — Since  it  is  seen 
that  the  product  of  the  pressure  and  volume  is  pro- 
portional to  the  change  in  absolute  temperature  we 
shall  now  write  one  of  the  most  useful  formulas  in 
the  computation  of  gas  constants,  namely  that 

pv  =  RT   (5) 

in  which  R  is  a  constant. 


Saturated  Steam  Obeys  not  at  all  the  Simple  Laws  of  Thermo- 
dynamics. (Circulating  Water  Pumps  Operated  by  Saturated  Steam 
at  the  Redondo  Plant  of  the  Pacific  Light  &  Power  Corporation.) 


In  the  case  of  air,  let  us  see  if  we  can  compute 
this  constant.  Experimentally  it  is  found  that  the 
volume  of  air  in  a  boiler  room  temperature  of  84°  F. 
is  13.71  cu.  ft.  per  Ib.  when  the  atmospheric  pressure 
is  14.7  Ib.  per  sq.  in.  Substituting  in  the  above  for- 
mula we  have  14.7  X  144  X  13.71  =  R  (459.6  +  84) . 
Therefore  R  =  53.3. 

A  Formula  for  Gas  Density. — If  we  let  y  be  the 
density  of  a  gas,  it  is  evident  that  it  has  a  value  equal 
to  the  reciprocal  of  v  in  the  above  equation.  In  other 
words  the  density  of  a  gas  is  the  weight  of  1  cu.  ft, 
under  standard  conditions  of  pressure  and  temperature. 
We  may  then  write  without  further  proof  the  formula, 


LAWS  OF  THERMODYNAMICS  49 


T 


(6) 


To  Compute  "R"  for  Any  Gas.  —  In  the  measure- 
ment of  gases  there  is  a  standard  pressure  and  tem- 
perature to  which  all  gas  volumes  and  densities  are 
reduced  in  order  to  have  some  basis  of  comparison. 
These  standard  conditions  are  the  '  temperature  of 
freezing  water  and  the  pressure  of  the  atmosphere  at 
sea-level. 

From  the  equation  last  written  above,  it  is  now 
evident  that  since  p  and  T  are  constant  for  all  gases 
under  this  standardized  method  of  comparison, 
then  the  product  of  R  and  y  must  also  be  constant. 
This  gives  us  a  method  or  rather  formula  by  which  we 
may  obtain  the  value  of  R  for  any  gas  if  we  know  its 
density.  The  molecular  weights  of  all  gases  may  be 
obtained  by  reference  to  any  standard  book  on  elemen- 
tary chemistry. 

Let  us  multiply  both  sides  of  the  above  equation 
by  the  molecular  weight  m  and  by  rearranging  the 
terms,  we  have 

pm 
Rm  =  - 

yT 

For  oxygen  y  =  0.089222  Ib.  per  cu.  ft.  at  atmos- 
pheric pressure  and  32°  F.  and  m  =  32. 

14.7  X  144  X  32 

.'.  Rm  =  -  -=1544. 

0.089222X491.6 

Since  this  product  Rm  is  always  a  constant,  we 
have  for  any  perfect  gas  that 

1544 


m 

This  formula  together  with  the  preceding  general 
formulas  for  pressures  and  volumes  now  enables  us  to 
ascertain  practically  all  the  constants  for  perfect  gases. 

As  an  example  let  us  assume  that  the  temperature 
of  an  escaping  chimney  gas  is  400°  F.  What  would  be 


50  FUEL  OIL  AND  STEAM  ENGINEERING 

the  density  of  the  nitrogen  content  of  the  escaping 
flue  gases?  First  find  the  value  for  R  for  nitrogen  for 
which  m  =  28. 

1544 

/.  R  = =54.98 

28 
Hence  since 


We  have  54.98 


T 
14.7  x  144 


459.6  +  400 
.  • .  y  =  .04475 

It  is  always  convenient  to  express  volumes  as 
the  number  of  cu.  ft.  per  Ib.  Hence  when  the  symbol 
V  is  used  it  will  mean  the  total  volume  content  of 
the  gas  under  consideration.  If  M  represents  the 
weight  of  this  volume  V  we  have  the  relationship 

Mv  =  V (8) 

or  since  pv  =  R  X  T,  therefore 

pV  —  MXRT    (9) 

Thus  if  we  have  given  18.805  Ib.  of  dry  flue  gas  we 
can  easily  compute  the  volume  it  would  occupy  when 
leaving  the  chimney  at  400°  F.,  if  it  is  known  that 
the  value  of  R  for  the  chimney  gas  is  51.4.  Thus 

14.7  X  144  V  =  18.805  X  51.4  X  (400  +  459.6) 
/.  V  =  393.5  cu.  ft. 

Further  Illustrative  Examples. — In  order  to  still 
further  illustrate  the  wide  uses  to  which  the  formulas 
above  given  may  be  applied  in  engineering  practice, 
the  following  seven  problems  are  worked  out  in  full  : 

1.  Find  the  volume  of  one  pound  of  air  in  a  compressor 
at  a  pressure  of  100  Ibs.  square  inch,  the  temperature  being 
32°  F. 

From    Boyle's    Law: 

p  v  =  PO  v0 
at  32°  F.,  v0  for  1  Ib.  of  air  is  12.39  cu.  ft.  and  p0  =  14.7  X  144 


LAWS  OF  THERMODYNAMICS  51 

14.7  X  144  X  12.39 


=  1.82  cu.  ft.— Ans. 


100  X  144 

2.  From  Charles'  Law  find  the  volume  of  one  Ib  of  air 
at  atmospheric  pressure  and  72°  F. 

t.  —  32  72  —  32 

v  =  v0(l  +  -      — )  =12.39  (1  +-  — )  =13.4  cu.  ft.— Ans. 

491.6  491.6 

3.  Find  the  temperature  of  two  ounces  of  hydrogen  con- 
tained in  one  gallon  flask  and  'exerting  a  pressure  of  10,000 
Ibs.  per  sq.  in. 

2  oz.  =  1  gal. 
16  oz.  =  1  Ib.  or  8  gals  =  1.068  cu.  ft. 

pv          10,000  X  144  X  1.068 
Then  T  = = 


R  765.86 

.'.  T  =  2050°  F.  (abs.)  —  Ans. 
or    t  =  2050  —  459.6  =  1590.4°  F.— Ans. 

4.  How  large  a  flask  will  contain  1  Ib.  of  Nitrogen  at  3200 
Ibs.  per  sq.  in.  pressure  and  70°  F.? 

p  =  3200X144,  T  =  459.6  +  70  =  529.6,   R  =  54.98 

RT 

pv  =  RT  v  =  — 

P 

54.98  X  529.6 

.•.v  =  —  —  =  .0631  cu.  ft. — Ans. 

3200  X  144 

5.  Ten  Ibs.  of  air  at  200°  F.  occupy  120  cu.  ft.     What 

must  be  the  pressure? 

V  =  120 
M=    10 
R=    53.33 
T  =  659.6 

MRT  10  X  53.3  X  659.6 

.'.p  — —  —  =  2950   Ib.   per  sq.   ft. 

V  120  Ans. 

6.  How  many  Ibs.  of  air  does  it  take  to  fill  5600  cu.  ft. 
at  15  Ibs.  per  sq.  in.  pressure  and  60°  F.? 

pV  =  MRT 
V  =  5600       p  =  15X144       R  =  53.3       T  =  459.6  +  60  =  519.6 

15  X  144  X  5600 

.•.M  =  —  —  =  437  Ibs. — Ans. 

53.3  X  5119.6 


CHAPTER  VI 

WATER  AND  STEAM  IN  FUEL  OIL  PRACTICE 


S  we  look  about  us  in  na- 
ture, we  find  that  all  in- 
animate creation  presents 
itself  to  us  in  three  dis- 
tinct physical  states.  Cer- 
tain bodies,  for  instance, 
of  themselves  readily 
maintain  their  shape  while 
others,  although  non  va- 
riant in  density,  neverthe- 
less seem  to  have  no  par- 
ticular physical  configura- 
tion but  seek,  due  to  the 
force  of  gravitation,  the 
lowest  level  attainable  and 
consequently  must  as  a. 
rule  be  held  in  a  cantain- 

A  Typical  Boiler^Settmg  in  Fuel    jng   yessel.       On    the    Other 

hand,     a     third     class     of 

bodies  is  found  not  only  possessing  no  particular  phys- 
ical configuration,  but  which  actually  seem  inherently 
desirous  of  expanding  to  such  an  extent  that  they  must 
as  a  rule  be  completely  housed,  bottom  and  top,  in  a 
containing  vessel. 

In  the  class  room  or  in  the  power  plant,  it  is  easy 
to  find  illustrations  of  these  three  general  classifica- 
tions. Thus,  chalk,  iron  pipe,  and  coal  are  instances 
of  the  first  division  and  are  known  as  solids.  Crude 
petroleum,  water,  and  kerosene  are  instances  of  the 
second  division,  and  are  called  liquids.  Finally,  air, 
steam,  and  producer  gas  illustrate  the  third  division, 
and  are  called  gases. 

52 


WATER  AND  STEAM  53 

These  States  are  Possible  to  all  Bodies.— The 
most  interesting  thing  about  these  socalled  states 
of  matter,  and  indeed  the  item  of  most  importance 
to  the  engineer,  is  that  by  varying  the  pressure  ex- 
ternally forcing  itself  against  the  sides  of  any  one  of 
these  bodies  and  by  adding  or  subtracting  the  heat  that 
may  be  held  in  store  within  the  body  itself,  any  solid 
may  be  converted  into  a  liquid  and  then  into  a  gas,  or 
any  liquid  may  be  converted  into  a  solid  or  a  gas,  or 
any  gas  may  be  converted  into  a  liquid  then  into  a 
solid. 

The  Fundamental  Principle  in  Steam  Engineering. 
—It  is  this  property  of  matter  that  makes  the  opera- 
tion of  the  steam  engine  possible.  For  if  we  were 
not  able  to  heat  water  and  convert  it  into  steam,  it 
would  be  impossible  to  make  use  of  this  liquid  for 
steam  engineering  purposes,  although  it  is  the  most 
widely  distributed  in  nature. 

Again,  since  fuel  oil  must  be  converted  into  the 
gaseous  state  before  it  readily  and  efficiently  burns 
beneath  the  boiler,  it  would  certainly  be  cumbersome 
and  impractical  for  its  use  in  the  great  majority  of 
central  stations  if  it  could  not  be  conveyed  through 
pipes  or  in  oil  tanks  as  a  liquid  from  the  oil  fields  to 
the  place  of  consumption. 

Steam  Engineering  Still  Supreme. — Since  water 
is  so  widely  disseminated  in  nature  and  since  it  can  be 
readily  and  efficiently  changed  from  one  state  to  an- 
other, it  is  the  working  substance  that  today  still 
drives  the  vast  majority  of  power  developing  mechan- 
isms in  the  industries  in  spite  of  the  rise  of  the  gas 
engine  and  the  great  modern  evolution  in  water  power 
development. 

Let  us  then  trace  the  physical  phenomena  that 
accompany  the  transformation  of  water  into  the  solid 
state  which  of  course  is  necessary  in  the  production 
of  ice,  and  again  from  the  liquid  to  the  gaseous  state 
which  becomes  necessary  in  the  production  of  steam. 

The  Formation  of  Ice. — Let  us  first  start  with  a 
pound  of  water  at  ordinary  temperatures — say  at  62°  F. 
As  we  begin  to  lower  the  temperature,  in  other  words 


54  FUEL  OIL  AND  STEAM  ENGINEERING 

to  draw  off  heat,  the  volume  slightly  decreases.  Thus 
the  pound  of  water  now  occupies  less  space  than  for- 
merly. Hence,  if  this  water  was  on  the  surface  of  a 
mountain  lake  and  the  night  was  getting  cooler,  the 
surface  water  would  sink  to  the  lake  bottom  and 
allow  warmer  water  from  the  bottom  to  rise  only 
to  be  cooled  at  the  surface  to  again  drop  to  the  bot- 
tom. This  is  what  is  known  as  water  circulation  and 
is  very  important  in  steam  generation,  as  we  shall 
see  later. 

When,  however,  the  water  under  consideration 
lowers  to  a  temperature  of  39.4°  F.,  a  strange  thing 
happens.  Something  develops  in  its  internal  struc- 
ture that  now  makes  the  water  expand  as  the  temper- 
ature is  further  lowered.  A  unit  volume  of  water  now 
becoming  lighter  than  formerly,  no  longer  will  it  sink 
to  the  lake  bottom  but  remains  on  the  surface.  Hence 
when  a  short  time  later  the  water  on  the  surface  is 
lowered  to  32°  F.  or  freezing  point,  ice  is  formed  on 
the  surface  only,  since  water  is  a  poor  conductor  of 
heat.  Nature  thus  protects  the  fish  in  the  waters 
below. 

Coming  back  from  the  mountain  lake,  however,  to 
the  formation  of  ice  in  the  ice  plant,  when  the  tem- 
perature has  reached  32°  F.,  although  heat  be  now 
driven  off,  the  water  does  not  lower  itself  in  temper- 
ature but  remains  at  this  temperature  until  it  has  all 
been  converted  into  ice. 

Latent  Heat  of  Fusion. — The  quantity  of  heat 
necessary  to  form  one  pound  of  ice  at  32°  F.  from  one 
pound  of  water  at  32°  F.  is  a  definite  measurable  quan- 
tity and  is  known  as  the  latent  heat  of  fusion.  By 
careful  measurement,  the  latent  heat  of  fusion  for 
water  has  been  found  to  be  142  B.t.u,  That  is,  to 
convert  one  pound  of  water  at  32°  F.  into  ice  at  32°  F. 
requires  the  drawing  off  of  as  much  heat  as  would 
approximately  be  required  to  lower  one  pound  of 
water  one  hundred  forty-two  degrees  in  temperature. 

When  this  pound  of  water  is  converted  into  ice, 
its  volume  still  further  expands.  Hence,  one  pound 
of  ice  will  float  in  water.  This  accounts,  of  course, 


WATER  AND  STEAM  55 

for  the  floating  of  icebergs  on  the  water  surface,  and 
furthermore  this  sudden  increase  in  volume  accounts 
for  the  rupture  in  pipes  and  other  nuisances  that  occur 
in  severely  cold  weather. 

Going  back  to  our  pound  of  water  now  converted 
into  a  pound  of  ice,  let  us  again  proceed  to  draw  off 
heat.  It  is  now  found  that  we  may  lower  the  tempera- 
ture of  the  ice  much  more  easily  than  when  it  existed 
as  a  liquid.  Indeed  only  about  one-half  the  heat  is 
required  to  be  drawn  off  per  degree  lowering  in  tem- 
perature while  its  volume  practically  remains  constant. 

The  Formation  of  Steam. — Let  us  now  proceed  to 
a  consideration  of  the  physical  changes  and  phenom- 
ena that  occur  when  water  passes  into  steam.  Start- 
ing with  water  at  say  62°  F.,  as  we  add  heat  the 
temperature  increases  at  the  rate  of  about  1°  F.  for 
every  unit  of  heat  energy  added  to  the  water.  At 
the  same  time  the  volume  slightly  increases.  Hence, 
if  our  pound  of  water  under  consideration  be  sit- 
uated at  the  bottom  of  the  well-known  tea-kettle, 
the  observation  of  which  led  James  Watt  to  the  inven- 
tion of  the  steam  engine,  this  pound  of  water 
becoming  now  less  dense  will  rise  to  the  top 
and  cooler  water  at  the  top  will  sink  to  the  bot- 
tom which  in  turn  is  passed  again  to  the  top  as  it 
becomes  heated  to  make  way  for  more  water  from 
the  top  to  be  heated  along  the  portion  exposed  to 
the  heat  application.  Thus  the  water  becomes  warmer 
and  warmer  and  the  transference  from  bottom  to  top 
continues.  The  ease  with  which  this  transfer  of 
heated  bodies  of  water  takes  place  has  much  to  do 
with  efficient  operation  of  the  steam  boiler  which  may 
be  likened  to  an  enlarged  tea-kettle  with  accessories 
and  appurtenances  to  care  for  its  increased  responsi- 
bilities as  compared  to  tea-kettle  operation. 

Latent  Heat  of  Evaporation. — The  water  in  this 
manner  continues  to  absorb  heat  until  if  under  atmos- 
pheric pressure,  it  reaches  a  temperature  of  212°  F. 
At  this  point,  however,  vast  quantities  of  heat  may  be 
added  and  still  the  water  will  remain  at  this  tempera- 
ture although  it  may  now  be  observed  that  steam  is 


56 


FUEL  OIL  AND  STEAM  ENGINEERING 


being  formed  which  too,  has  the  same  temperature 
as  the  water.  Not  until  970.4  B.t.u.  or  sufficient  heat 
units  to  raise  ten  pounds  of  water  almost  one  hundred 
degrees  in  temperature  have  been  added  to  the  pound 
of  water  at  212°  F.  will  the  pound  of  water  become 


300 


£00 


190 


HEAT   UNITS  ,N     B.TM. 


200 


+00         600         GOO         tOOO        1200 


THE    TEMPERATURE     HEAT    DIAGRAM 

Here  is  graphically  indicated  the  history  of  a  pound  of  water  in  its 
relationship  with  temperature  and  heat.  Beginning  at  32  deg.  F. 
and  atmospheric  pressure,  by  drawing  off  heat  the  horizontal  line 
ab  is  traced,  showing  that  the  temperature  remains  constant  until 
the  water  is  completely  converted  into  ice,  after  which  the  tem- 
perature rapidly  falls  at  the  rate  of  about  one  degree  for  every 
half  unit  of  heat  drawn  away.  By  the  addition  of  heat,  however, 
at  point  a,  the  curve  ae  is  traced,  which  indicates  that  the  tem- 
perature rises  with  absorption  of  heat  at  the  approximate  rate  of 
one  degree  for  each  unit  of  heat  absorbed.  At  -212  deg.  F.  and 
atmospheric  pressure  the  horizontal  line  eg  is  traced  until  970.4 
B.t.u.  are  absorbed.  After  all  the  water  is  thus  converted  into 
steam  the  curve  gh  is  traced  for  superheated  steam,  which  rises 
at  the  rate  of  about  one  degree  for  every  .47th  of  a  B.t;u.  absorbed. 

entirely  converted  into  steam  at  212°  F.  This  quan- 
tity of  heat  necessary  is  important  in  steam  engineer- 
ing and  is  known  as  the  latent  heat  of  evaporation 
for  water  under  atmospheric  pressure  conditions.  To 


WATER  AND  STEAM  57 

be  succinct,  in  steam  engineering  practice  the  quantity 
of  heat  necessary  to  convert  one  pound  of  water  at  a 
given  temperature  and  pressure  into  dry  steam  at  the 
same  temperature  and  pressure  is  known  as  the  latent 
heat  of  evaporation  for  that  temperature  and  pressure 
and  is  usually  expressed  by  the  symbol  Lt.  Steam 
boilers  seldom  operate  at  a  pressure  so  low  as  that  of 
atmospheric  conditions.  Indeed,  while  such  a  pressure 
is  but  14.7  Ib.  per  sq.  in.,  the  modern  boiler  in  the  cen- 
tral station  operates  at  something  like  ten  to  fifteen 
times  this  pressure.  This  fact  materially  complicates 
computation  in  steam  engineering,  for  it  is  found  that 
at  pressures  different  than  that  of  standard  atmos- 
pheric conditions  the  latent  heat  of  evaporation  is 
wholly  different.  Indeed,  so  complex  is  this  law  of 
variation  that  no  one  as  yet  has  been  able  to  give  an 
exact  formula  for  its  determination,  although  in  sub- 
sequent chapters  approximate  equations  will  be  set 
forth.  Hence,  it  has  become  necessary  to  refer  to 
carefully  compiled  steam  tables  for  such  information 
and  a  later  chapter  will  set  forth  the  manner  of  their 
use. 

Other  Variations  Occur  With  Changes  of  Pres- 
sure.— When  water  passes  into  steam,  the  volume — 
say  of  one  pound — vastly  increases.  At  atmospheric 
pressure  the  volume  of  steam  is  about  sixteen  hun- 
dred times  what  it  was  when  existing  as  water.  At 
other  pressures  the  volume  relationships  will  of 
course  be  different.  Again  when  the  pressure  in- 
creases at  which  steam  is  formed,  the  volume  be- 
comes less  in  proportion.  No  accurate  mathematical 
formula  has  been  found  for  this  relationship,  hence 
once  again  must  we  appeal  to  the  steam  tables. 

Data  Easily  Taken  from  Steam  Tables.— By  ex- 
periment it  has  been  found  that  varying  amounts  of 
heat  are  required  to  raise  water  from  a  particular 
initial  temperature  to  the  boiling  point,  for  the  boil- 
ing point  is  not  reached  until  a  higher  temperature 
is  attained  as  the  pressure  is  increased.  On  the  other 
hand,  less  heat  is  required  to  convert  a  pound  of 
water  at  these  higher  boiling  points  into  steam.  Since 


58  FUEL  OIL  AND  STEAM  ENGINEERING 

the  volume  and  density  too  vary  under  varying  pres- 
sures, the  entire  problem  now  becomes  one  of  picking 
the  proper  constants  for  the  particular  temperature 
and  pressure  under  discussion  and  when  one  by  a 
little  practice  can  use  the  steam  tables  with  facility, 
it  is  surprising  to  see  how  simply  and  directly  most 
problems  in  steam  computation  may  be  solved. 

Total  Heat  of  Steam. — Often  in  steam  engineer- 
ing practice  problems  arise  in  which  we  must  express 
the  total  heat  of  steam  quantitatively  represented  in 
each  pound  under  consideration.  It  makes  little  dif- 
ference at  what  point  we  begin  to  estimate  such 
heat  relationships,  but  by  common  consent  the  freez- 
ing point  of  water  has  been  adopted.  Hence,  the  total 
heat  of  steam  is  the  heat  required  to  raise  one  pound 
of  water  from  32°  F.  to  the  boiling  point  added  to  the 
heat  required  to  convert  this  water  into  steam  at 
that  temperature.  If  the  steam  exist  as  superheated 
steam,  there  must  also  be  added  the  heat  required  to 
raise  dry  saturated  steam  to  the  temperature  of  super- 
heat. The  various  mathematical  formulas  for  com- 
puting these  numerical  results  will  be  taken  up  later 
in  a  chapter  entitled  Quality  of  Steam. 

At  this  particular  time  we  shall  write  down  the 
simplest  of  these  formulas  as  an  illustration. 

Total  Heat  of  Dry  Saturated  Steam.— The  total 
heat  of  dry  saturated  steam,  written  Ht  for  a  given 
temperature  t,  is  the  sum  of  the  heat  of  liquid  and 
latent  heat  of  evaporization  for  that  temperature. 

Hence  we  may  write  this  important  fundamental 
equation 

Ht  =  ht  +  Lt    ' (1) 

Thus  the  total  heat  of  steam  at  212°  F.  is 

Ht  =  180  +  970.4=  1150.4  B.t.u. 

Other  Instances  of  Total  Heats. — If,  however,  the 
steam  is  evaporated  from  the  water  and  then  super- 
heated, that  is,  an  additional  quantity  of  heat  is  added 
after  all  the  water  has  become  steam,  it  will  then  begin 
to  rise  in  temperature  and  the  quantity  of  heat  neces- 


WATER  AND  STEAM  59 

sary  for  each  degree  rise  in  temperature  is  about  one- 
half  that  required  per  degree  rise  when  it  existed  as 
water.  This  exact  ratio  is  however  quite  variable  and 
ranges  between  .46  and  .60  depending  upon  the  pres- 
sure and  degree  of  superheat  attained.  Hence  once 
again  appears  the  necessity  of  steam  tables. 

It  is  now  readily  seen  that  in  general  three  definite 
and  distinct  considerations  present  themselves  in  the 
solution  of  problems  involving  the  computation  of 
total  heat.  The  first  instance  is  one  in  which  the 
steam  exists  in  a  dry  state  and  at  the  temperature  and 
pressure  at  which  it  is  generated  from  the  water.  Such 
steam  is  known  as  dry  saturated  steam.  The  second 
instance  is  that  in  which  the  steam  is  not  completely 
dry,  but  holds  in  suspension  small  particles  or  globules 
of  water,  and  in  this  instance  the  mixture  is  known 
as  wet  saturated  steam.  The  third  instance  is  of 
especial  importance  in  modern  central  station  practice 
and  involves  what  is  known  as  superheated  steam.  In 
this  case  the  steam  is  first  formed  by  evaporation  from 
water  into  dry  saturated  steam,  after  which  it  is  con- 
veyed through  pipes  that  are  exposed  to  high  tem- 
peratures, thus  causing  the  temperature  of  the  steam 
to  be  still  further  raised,  although  the  pressure  prac- 
tically remains  constant. 

The  complete  solution  of  these  three  instances  for 
computation  of  total  heats  will  be  found  in  the  chap- 
ter on  Quality  of  Steam  as  stated  above.  Meanwhile 
the  thorough  mastery  of  the  fundamentals  of  the  phys- 
ical properties  of  water  as  herein  set  forth  will  be  of 
vast  assistance  in  a  clear  understanding  of  this  later 
discussion. 
Examples 

1.  The  water  entering  a  feed-water  heater  is  at  a  tem- 
perature of  75°  F.  and  leaves  the  heater  at  190°  F.,  what  is 
the  heat  absorbed  per  Ib.  of  water? 

From  the  steam  tables  the  heat  of  liquid  at  75°  F.  is 
43.05  B.t.u.  and  at  190°  F.  it  is  157.91  B.t.u.  Hence  the  heat 
absorbed  per  Ib.  of  water  is 

157.91  —  43.05  =  114.86  B.t.u. — Ans.' 

2.    Waiter  enters  a  boiler  at  160°  F.  and  is  converted  into 
dry  saturated  steam  at  200  Ib.  pres,  per  sq.  in.  abs.,  what  is 


60  FUEL  OIL  AND  STEAM  ENGINEERING 

the  total  heat  required  to  evaporate  each  Ib.  of  steam? 

The  heat  in  the  entering  water  at  160°   P.  fs  from  the 
steam  tables  127.86  B.t.u.     The  total  heat  of  dry  saturated 
steam  at  200  Ib.  pres.  abs.,  i*s  1198.1  B.t.u.     H'ence  the  actual 
heat  necessary  to  evaporate  each  Ib.  of  steam  is 
1198.10  — 127.86  =  1070.24   B.t.u.— Ans. 

3.  If  the  heat  of  liquid  for  boiling  water  at  212°  F.  is 
180  B.t.u.  and  the  latent  heat  of  evaporation  is  970.4  B.t.u., 
how  much  heat  is  required  to  evaporate  a  pound  of  water 
from  an  open  water  heater  which  is  receiving  its  supply  at 
64°  F.? 

Each  Ib.  of  water  entering  at  64°  F.  has  a  heat  of  liquid 
of  32.07  B.tu.  Water  evaporating  into  steam  at  212°  F. 
has  a  heat  of  liquid  of  180  and  a  latent  heat  of  evaporation  of 
970.4  B.t.u.,  making  a  total  heat  of  evaporation  of  1150.4  B.t.u. 
for  every  Ib.  of  water  so  evaporated.  Hence  the  net  heat 
required  is  1150.40  —  32.07  =  1128.33  B.t.u.— Ans. 


CHAPTER  VII 


THE  STEAM  TABLES  IN  FUEL  OIL  PRACTICE 

T  has  already  been  shown 
that  since  no  simple 
mathematical  laws  have  as 
yet  been  devised  to  ex- 
press the  temperature, 
pressure,  latent  heat,  heat 
of  liquid  and  other  funda- 
mental properties  of  steam 
and  water  that  are  abso- 
lutely necessary  in  the 
solution  of  steam  engi- 
neering problems,  we  must 
resort  to  carefully  com- 
piled steam  tables. 

Practically    all    the    re- 
search   and    scientific    in- 
vestigation along  the  lines 
of     pure  steam  engineer- 
ing   of    the    last    half    century    have    been    devoted 
to   the   more   complete  establishment  of  some  of  the 
fundamental  constants  involved  in  the  steam  tables. 

The  three  most  important  of  these  are  the  zero 
point  of  the  absolute  temperature  scale,  the  proper 
value  for  a  constant  employed  in  the  conversion  of 
mechanical  energy  into  heat  energy,  and  the  exact 
determination  of  the  heat  required  to  evaporate  one 
pound  of  water  from  212°  F.  into  dry  saturated  steam 
at  212°  F. 

Since  these  values  are  continually  found  by  more 
careful  and  exacting  experimental  work  to  be  slightly 
different  than  formerly  held,  we  find  that  the  steam 
tables  of  recent  publication  are  different  than  those  of 
former  years. 


The  Book  of  Steam  Tables 


61 


62  FUEL  OIL  AND  STEAM  ENGINEERING 

The  Steam  Tables  as  Adopted  in  this  Discussion. 

— The  Steam  Tables  and  Diagrams  as  computed  by 
Marks  and  Davis  and  published  by  Longmans,  Green 
&  Company  are  today  universally  recognized  and  are 
adopted  as  the  standard  compilation  for  the  problems 
cited  in  this  discussion. 

In  the  rear  of  these  steam  tables  an  interesting 
discussion  of  the  methods  employed  by  these  inves- 
tigators in  arriving  at  the  three  fundamental  con- 
stants mentioned  above  is  given.  The  result  of  these 
investigations  shows  that  the  absolute  zero  is  to  be 
taken  at  —  459.6°  F.,  the  mechanical  equivalent  of  heat 
at  777.5,  and  the  latent  heat  of  steam  at  212°  F.  to 
be  970.4  B.t.u. 

Recapitulation    of    Fundamental     Evaluations. — 

These  three  constants  are  so  important  that  they 
should  be  memorized  and  for  emphasis  let  us  recapit- 
ulate their  exact  interpretation. 

The  absolute  zero  is  now  found  to  be  a  point  sit- 
uated at  459.6°  F.  below  the  zero  point  on  the  Fahren- 
heit scale  or  491.6°  F.  below  the  freezing  point  of 
water.  At  such  a  temperature  it  is  supposed  to  be 
impossible  to  further  draw  off  heat  from  any  substance 
for  at  this  temperature  the  heat  storage  is  supposed 
to  be  absolutely  exhausted. 

The  mechanical  equivalent  of  heat  as  given  above 
means  that  the  energy  represented  by  one  B.t.u.  or 
British  thermal  unit  of  heat  is  equivalent  to  777.5  ft. 
Ib.  of  mechanical  energy.  Or  if  one  pound  of  crude 
petroleum  contains  18,500  B.t.u.,  it  possesses  as  stated 
in  a  previous  chapter,  sufficient  energy  to  raise  a 
human  being  weighing  175  Ib.  a  vertical  upward  dis- 
tance of  over  18  miles. 

The  latent  heat  of  steam  at  212°  F.  and  atmos- 
pheric pressure  means  that  the  quantity  of  heat  neces- 
sary to  evaporate  one  pound  of  water  at  212°  F.  into 
dry  saturated  steam  at  212°  F.  is  found  experimentally 
to  be  970.4  B.t.u. 

Analysis  of  a  Typical  Page  of  Steam  Tables.— Let 

us  now  proceed  to  analyze  a  page  of  Marks  &  Davis' 


STEAM  TABLES  63 

steam  tables,  column  by  column.  The  illustration  as 
given  is  found  on  page  12  of  this  compilation  and  we 
shall  follow  across  the  page  the  line  corresponding 
to  a  temperature  of  231°F. 

Temperatures  in  Fahrenheit  Units. — Since  all 
steam  engineering  computation  is  based  on  temper- 
atures represented  in  the  Fahrenheit  scale  instead  of 
the  Centigrade  system,  the  temperatures  are  here 
listed  in  the  Fahrenheit  units. 

Pressures  in  Absolute  Notation. — This  column 
means  that  the  pressures  here  given  represent  the 
pressure  in  pounds  per  sq.  in.  at  which  water  will  boil 
when  the  temperature  is  that  as  listed  in  the  first 
column.  Further  on  in  the  steam  tables  an  exactly 

Table  1 :  Temperatures 

,.  „          >M              Sp.Vol.    Density       Heat     Latent     Total        Internal  Energy                   Entropy  T 

Temp.         Pressure          £  ft<    )bs  pe{      ofthe    heatof  heat  of  B  tu     "     / J2 1    Temp. 

Fahr.  Ibs.  Atmos*  per  Ib.  cu.    ft.  liquid  evap.  steam  Evap.     Steam  Water      Evap.     Steam  Fahr. 

t           p         -  vors       Vv  horq  Lorr;      H  lorp       E  nor«  L/Torr/T  Nor*  t 

230°  20.77  1.413  19.39  0.0516  198.2  958.7  1156.9  884.3  1082.4  0.3384  1.3905  1.7289  2309 

231  21.16  1.440  19.05  0.0525  199.2  958.1  1157.2  883.6  1082.7  0.3399  1.3875  1.7274  231 

232  21.56  1.467  18.72  0.0534  200.2  957.4  1157.6  882.8  1083.0  0.3414  1.3844  1.7258  232 

233  21.%  1.494  18.40  0.0543  201.2  956.7  1158.0  882.1  1083.2  0.3429  1.3814  1.7243  233 

234  22.37  1.522  18.09  0.0553  202.2.  956.1  1158.3  881.3  1083.5  0.3443  1.3784  1.7227  234 

235°  22.79  1.550  17.780.0562  203.2  955.4"  1158.7  880.61083.8  0.34581.37541.7212  235° 

236  23.21  1.579  17.47  0.0572  204.2  954.8  1159.0  879.8  1084.0  0.3472  1.3725  1.7197  236 

237  23.64  1.609  17.17   0.0582  205.3  954.1  1159.4  879.1  1084.3  0.3487  1.3695  1.7182  237 

238  24.08  1.638  16.88  0.0592  206.3  953.4  1159.7  878.3  10S4.5  0.3501  1.3666  1.7167  238 

239  24.52  1.668  16.60  0.0602  207.3  952.8  1160.0  '.  877.6  1084.8  0.3516  1.3636  1.7152  239 

240°  24.97  1.699  16.32  0.0613  208.3  952.1  1160.4  876.8  1085.0  0.3531  1.3607  1.7138  240° 

241  25.42  1.730  16.05  0.0623  2093  951.4  1160.7  876.1  1085.3  0.3546  1.3578  1.7124  241 

242  25.88  1.761  15.78  0.0634  210.3   950.7  1161.1  875.3  1085.6  0.3560  1.3550  1.7110  242 

243  26.35  1.793  15.52  0.0644  211.4  950.1  1161.4  874.6  1085.8  0.3575  1.3521  1.70%  243 

244  26.83  1.826  15.26  0.0655  212.4  949.4  1161.8  873.8  1086.1  0.3589  1.3493  1.7082  244 

A  Typical  Page  from  the  Steam  Tables 

similar  table  may  be  found  to  the  one  cited  except  in 
this  latter  instance  the  pressures  are  made  to  vary 
pound  by  pound  and  the  corresponding  boiling  tem- 
perature of  water  given. 

In  this  instance,  then,  we  read  that  a  pressure  of 
21.16  Ib.  per  sq.  in.  will  be  produced  before  the  water 
boils  or  the  formation  of  steam  begins  at  231°  F.  This 
pressure,  by  the  way,  is  in  absolute  units  and  would 
not  be  the  pressure  read  on  the  steam  gage  of  a  boiler 
room.  Since  the  steam  gage  indicates  pressures  above 
the  atmosphere,  one  must  subtract  from  this  reading 
in  the  steam  tables  the  atmospheric  pressure  of  the 


64 


FUEL  OIL  AND  STEAM  ENGINEERING 


day  in  order  to  find  the  proper  gage  pressure.  Thus, 
in  this  instance,  if  the  atmospheric  pressure  of  the  day 
be  14.7  Ib.  per  sq.  in.,  a  steam  gage  in  a  boiler  room 


1010 

c 


LOGO 


Marks  &  Davis  Method  of  Collating  Data  for  Specific 
Heat  of  Water  from  Three  Noted  Investigators 

would  read  6.46  Ib.  per  sq.  in.,  when  the  water  in  the 
boiler  is  231°  F. 

This  precaution  is  most  important  and  the  stu- 
dent should  carefully  reread  the  former  chapter  on 
pressures  if  he  does  not  thoroughly  understand  the 
conversion  of  gage  pressures,  inches  of  vacuum, 
inches  of  mercury,  etc.,  into  standard  absolute  pres- 
sure units. 

Pressures  in  Atmospheres. — In  many  engineering 
computations  pressures  are  given  as  so  many  atmos- 
pheres instead  of  pounds  per  square  inch.  The  pres- 
sure of  the  standard  atmosphere  is  usually  taken  as 
14.7  Ib.  per  sq.  in.  but  for  very  exact  work  it  is  more 
accurately  14.696  Ib.  per  sq.  in.  Hence  this  column 
is  computed  by  dividing  each  item  in  the  preceding 
column  by  14.696,  which  in  this  instance  is  found  to 
be  1.440  atmospheres. 

When,  however,  the  reading  is  below  that  of 
ordinary  atmospheric  pressure,  such  values  are  often 


STEAM  TABLES  65 

desired  in  inches  of  mercury  since  vacuum  pressures 
for  the  condenser  are  given  in  such  units.  This  par- 
ticular column  is  therefore  found  by  dividing  the  cor- 
responding line  in  the  preceding  pressure  column  by 
the  number  of  inches  of  mercury  equivalent  to  one 
pound  pressure  per  square  inch.  It  is  to  be  remem- 
bered that  this  does  not  even  yet  give  the  reading  in 
inches  of  vacuum.  Pressures  in  absolute  inches  of 
mercury,  and  inches  of  vacuum  cause  seemingly  end- 
less confusion.  A  complete  discussion  of  this  feature 
was  taken  up  under  the  chapter  on  pressures  and  its 
careful  review  is  emphatically  recommended  if  arijr 
unsettled  question  still  exists  in  the  mind  of  the 
reader. 

Specific  Volume. — The  cubic  feet  occupied  by  one 
pound  of  dry  saturated  steam  at  a  given  temperature 
and  pressure  is  known  as  the  specific  volume  of  the 
steam  for  that  temperature  and  pressure. 

This  is  a  factor  often  necessary  in  steam  engineer- 
ing computations.  Yet  no  known  means  has  ever 
been  invented  whereby  this  factor  can  be  accurately 
ascertained  by  experiment.  The  task  is  indeed  one 
that  involves  such  difficulties  as  to  make  its  determi- 
nation by  experiment  practically  impossible.  The 
science  of  higher  mathematics  has  come  to  the  rescue 
and  here  is  indeed  an  instance  where  purely  theoretical 
deductions  have  brought  about  a  practical  solution 
of  an  otherwise  unsolvable  problem  in  steam  engineer- 
ing 

This  relationship  involves  the  latent  heat  of  evap^ 
oration  L ;  the  absolute  temperature  T  at  which  the 
saturated  steam  is  formed;  the  ratio  of  the  increase 
in  pressure  A  p  to  the  increase  in  temperature  A  t  of 
boiling  points  taken  immediately  below  the  tempera- 
ture under  consideration  and  immediately  above  it; 
the  specific  volume  of  the  steam  v  that  is  found,  which 
of  course,  is  the  unknown  value  we  are  desirous  of 
computing;  and  the  specific  volume  of  a  space  occu- 
pied by  one  pound  of  water  vt  immediately  before  its 
conversion  into  steam.  Algebraically  the  relationship 
is  expressed  thus : 


66  FUEL  OIL  AND  STEAM  ENGINEERING 

Ap 


At 


(v-vj    ....................  (1) 


From  the  steam  tables  we  will  take  our  values 
for  A  p  and  A  t  immediately  below  corresponding  to 
230°  F.  and  immediately  above  corresponding  to 
232°F.  Hence 

At—  (232  —  230)  =2. 

Ap=  (21.56  —  2077)  144  =  0.79  X  144=114. 

T  —  231+459.6  =  690.6. 

L  =  958.1X777.5. 
Vl  =  .016  cu.  ft. 

Substituting,  we  have 

114 
958.1  X  777.5  =  690.6  (  -  )   (v  —  .016) 

2 
.'.v=  18.98 

The  value  in  the  table  is  19.05  which  is  seen  to 
be  about  one-third  of  one  per  cent  in  error.  This  dif- 
ference is  probably  due  to  the  fact  that  decimals 
neglected  in  computation  were  made  use  of  by  the 
compiler  of  the  steam  tables,  and  then  too  the  small 
pressure  and  temperature  variations  were  probably 
taken  nearer  together  than  is  possible  in  the  data 
actually  set  forth  in  the  steam  tables. 

Specific  Density.  —  The  weight  in  fractions  of  a 
pound  of  one  cubic  foot  of  dry  saturated  steam  is 
known  as  its  specific  density. 

It  is  evident  that  if  one  pound  of  steam  occupies 
19.05  cu.  ft.  as  taken  from  the  previous  column,  then 
1  cu.  ft.  of  steam  would  weigh  1/19.05  of  a  pound 
which  is  0.0525  Ib.  Hence  this  column  is  computed  in 
each  case  by  taking  the  reciprocal  of  the  data  given 
in  the  preceding  column. 

The  Heat  of  Liquid.  —  This  is  one  of  the  most 
important  columns  necessary  in  steam  engineering 
practice.  Since  the  heat  of  liquid  technically  means 
the  quantity  of  heat  necessary  to  raise  one  pound  of 
water  from  32°  F.  to  the  temperature  under  consider- 


STEAM  TABLES 


67 


ation,  it  is  evident  that  by  experimental  data  as  given 
in  this  column  it  has  been  found  that  to  raise  one 
pound  of  water  from  32°  F.  to  231°  F.,  199.1  B.t.u. 
are  necessary  to  be  applied  from  an  outside  source. 


Determination   of  the   Specific  Heat  of  Superheated 
S'team  from  Investigations  of  Knoblauch. 

The  Latent  Heat  of  Evaporation. — Data  for  the 
latent  heat  of  evaporation  has  been  determined  by 
careful  experimental  means.  It  is  by  definition  the 
quantity  of  heat  necessary  to  convert  one  pound  of 
water  at  the  temperature  and  pressure  indicated  into 
dry  saturated  steam  at  the  same  temperature  and 


68  FUEL  OIL  AND  STEAM  ENGINEERING 

pressure.  In  this  instance  it  is  seen  that  to  convert 
one  pound  of  water  at  231°  F.  into  dry  saturated 
steam  at  231°  F.,  958.1  B.t.u.  are  necessary  to  be  ap- 
plied from  an  outside  source. 

Total  Heat  of  Dry  Saturated  Steam.— The  total 
quantity  of  heat  required  to  raise  the  temperature 
of  one  pound  of  water  at  32°  F.  to  the  temperature  at 
which  dry  saturated  steam  may  exist  under  the  pres- 
sure exerted  in  the  particular  instance,  added  to  the 
quantity  of  heat  then  necessary  to  convert  this  water 
completely  into  dry  saturated  steam  is  known  as  the 
total  heat  of  dry  saturated  steam.  Numerically  speak- 
ing, it  is  seen  that  this  column  is  at  once  obtained 
by  adding  the  heat  of  liquid  and  the  latent  heat  of 
evaporation.  In  a  word,  this  column  is  the  sum  of 
the  two  preceding  columns.  Thus 

H23i  =  n23i  +  L231   (2) 

.-.H2S1  =  199.1  +  958.1  =  1157.2. 

Internal  and  External  Work. — One  wonders  where 
the  heat  disappears  when  it  is  being  continually  ap- 
plied to  water  at  the  boiling  point  and  yet  the  temper- 
ature of  the  water  or  steam  does  not  increase. 

Up'on  careful  investigation  it  is  found  that  it  dis- 
appears first  in  an  internal  absorption  due  to  inter- 
molecular  rearrangement  as  water  passes  into  steam 
which  thereby  stores  up  a  considerable  quantity  of 
energy  to  be  given  out  again  when  the  steam  is  con- 
densed back  into  water.  The  energy  that  disappears 
in  this  manner  is  known  as  energy  necessary  to  per- 
form internal  work. 

On  the  other  hand  in  the  generation  of  steam  from 
water  the  volume  is  vastly  increased.  The  pushing 
back  against  external  pressure  to  make  room  for  such 
an  increased  volume  performs  external  work.  So  that 
the  energy  applied  in  steam  generation  which  goes 
toward  latent  heat  of  evaporation  may  be  divided  into 
two  classifications,  known  as  external  and  internal 
work. 

No  one  has  as  yet  found  a  method  of  directly 
measuring  internal  work.  We  may,  however,  meas- 


STEAM  TABLES 


69 


are  external  work  or  even  compute  it  and  then  by 
subtraction  from  total  energy  absorbed  arrive  at  a 
value  for  internal  work. 

In  a  former  chapter  on  gases  it  was  shown  that 
the  external  work  accomplished  by  a  gas  expanding 
under  constant  temperature  and  pressure  is  com- 
puted universally  by  subtracting  the  initial  volume 
from  the  final  volume  and  then  multiplying  this  re- 
sult by  the  pressure.  Thus 

External  Work  ==  p  (v  —  vj 
To  convert  this  into  B.t.u.,  we  have 


External  Work  = 


P  (v  — 


(3) 


777.5 

From  the  tables  it    is    seen    that    in    this    instance 
p  =  21.16  X  144,  v  =  19.05,  Vl  =  .016. 

.'.  External  Work  =  21.16  X  144  (19.05  —  .016) 

=  74.6  B.t.u. 
/.  Internal  Work  =  958.1  —  74.6  =  883.5  B.t.u. 

Entropy  of  Water.  —  In  certain  advanced  prob- 
lems in  steam  engineering,  engineers  and  physicists 
have  found  it  convenient  to  invent  fictitious  qualities 
of  steam.  While  many  have  endeavored  to  give  a 


auu 
600 

6 

zoo 

0 

a 

1 

(. 

<~> 

^ 

65 

bi 

>.a 

™      Ol 

i 

' 

'rea 

^.-r 

^7//1 

1 

^ 

2/4            t 

>               t 

/O            tZ           14           16       1.7! 

THE    TEMPERATURE    ENTROPY    DIAGRAM 

By  the  invention  of  a  fictitious  quality  of  water  and  steam,  known 
as  entropy,  the  plotting  of  a  diagram  is  made  possible,  so  that  an 
area  represents  heat  added.  Thus,  in  the  diagram  above,  the 
abscissas  are  entropy  and  the  ordinates  'absolute  temperatures. 
The  area  abcf  is  exactly  180  units,  which  is  the  heat  required  to 
raise  water  from  32  deg.  F.  to  212  deg.  F.  Similarly,  the  area  fcde 
is  970.4  units,  which  is  the  heat  required  to  evaporate  one  pound 
of  water  at  212  deg.  F.  into  steam  at  212  deg.  F. 


70  FUEL  OIL  AND  STEAM  ENGINEERING 

physical  interpretation  of  entropy,  perhaps  it  is  clearer 
for  the  student  to  consider  it  as  merely  a  mathemat- 
ical fiction  which,  however,  often  becomes  extremely 
useful  for  the  representation  of  steam  engineering 
problems  and  indeed  assists  wonderfully  in  their  solu- 
tion. 

On  this  assumption,  entropy  may  be  defined  as 
such  a  quantity  that  when  plotted  against  absolute 
temperatures  the  area  under  the  curve  connecting  all 
such  points  will  numerically  represent  the  amount  of 
heat  supplied  to  one  pound  of  matter  in  order  to 
accomplish  the  indicated  change  in  temperature.  Thus 
in  the  instance  at  hand  if  one  should  plot  a  curve 
with  ordinates  representing  absolute  temperatures  and 
with  abscissas  representing  the  entropy  for  each  cor- 
responding temperature,  the  area  under  this  curve 
would  be  exactly  199.1  units.  For  it  takes  199.1 
units  of  heat  energy  to  raise  one  pound  of  water  from 
32°  F.  to  231°  F.  or  on  the  absolute  scale  from 
491.6°  F.  to  690.6°  F. 

By  analysis  in  higher  mathematics  it  is  found 
that  entropy  of  water  may  be  quite  closely  computed 
by  the  formula 


(9  =  loge-     - (4) 

T, 

Wherein  6  is  the  entropy  of  water,  T2  the  absolute 
temperature  at  the  end  of  the  heat  application  and  Tx, 
the  absolute  temperature  at  the  beginning  which  is 
usually  taken  at  the  melting  point  of  ice  or  491.6°  F. 
on  the  absolute  scale.  Thus  in  this  instance 

T2  231+459.6 

6  =  loge =  loge(-  -) 

T!  32  +  459.6 

(690.6) 

=  2.306  Iog10 =  .3399. 

(491.6) 

The  values  in  the  steam  tables  were  arrived  at 
by  a  slightly  more  accurate  process  than  this  by  tak- 


STEAM  TABLES  71 

ing  into  account   the   fact   that   the   specific   heat   of 
water  is  not  constant  as  heat  is  added. 

The  Entropy  of  Evaporation. — Since  the  tem- 
perature remains  constant  during  the  evaporation  of 
water  into  dry  saturated  steam,  it  is  evident  that  the 
entropy  curve  in  this  case  would  simply  be  a  rectangle 
as  shown  in  the  illustration  wherein  one  dimension 
is  of  length  T  and  the  area  swept  off  is  of  L  units. 
Hence,  the  entropy  for  heat  of  evaporation  is  evidently 

L 

Entropy  of  evaporation  = (5) 

T 
or   in   this    instance, 

958.1 

Entropy  of  evaporation  = — 

231  +  459.6 

=  1.3875 

Total  Entropy. — The  sum  of  the  entropy  value  for 
water  and  for  heat  of  evaporation  is  called  the  total 
entropy  of  dry  saturated  steam.  This  is  evidently 
arrived  at  numerically  by  adding  together  the  two 
preceding  columns.  Thus,  total  entropy  =  entropy 
of  water  +  entropy  of  evaporation (6) 

. ' .  Total  entropy  =  0.3399  +  1.3875  =  1.7274. 

Tables  for  Superheated  Steam. — In  later  pages  of 
the  steam  tables  are  to  be  found  data  relative  to  su- 
perheated steam.  As  a  subsequent  chapter  will  deal 
largely  with  superheated  steam  computations,  we 
shall  delay  the  consideration  of  superheated  steam 
tables  until  the  reader  has  been  more  thoroughly 
grounded  in  other  fundamental  computations  of  dry 
saturated  steam. 


CHAPTER  VIII 


HOW  TO   COMPUTE  BOILER  HORSEPOWER 

HAT  energy  is  never  cre- 
ated  or  destroyed  is  a 
fundamental  postulate  of 
modern  engineering  prac- 
tice. All  of  our  machines 
and  driving  mechanisms 
are,  then,  simply  devices 
by  means  of  which  we 
may  convert  one  form  of 
energy  into  another  form 
to  suit  our  convenience 
or  meet  the  demands  of 
industrial  activity.  Thus 
an  electric  generator  does 
not  create  energy  but  is 
merely  a  device  whereby 
energy  existing  in  the 
waterfall  or  in  the  steam 

How   James   Watt   would   Have          ,  .  ,  , 

standardized  a  Mechanical  turbine  may  be  converted 
S°So^ione  P  a  n  a  m  a-  into      electrical      energy. 

Neither   does   the   energy 

exist  inherently  in  the  waterfall,  but  due  to  the  emis- 
sion of  heat  from  the  sun,  this  water  has  first  been 
drawn  from  the  ocean  into  the  clouds  to  be  later  de- 
posited on  the  lofty  mountain  peaks.  Due  to  this  su- 
perior position  it  is  ena'bled  to  develop  water  power 
energy  and  thus  transfer  the  energy  of  the  sun's  rays 
into  more  useful  form  to  ease  man's  burdens.  And  so 
with  the  steam  boiler,  we  have  fundamentally  a  me- 
chanism by  which  energy  latent  in  fuel  oil  or  other 
combustible  is  first  given  out  as  heat  energy  of  com- 
bustion to  be  immediately  converted  into  latent  heat 
energy  of  steam. 

72 


BOILER  HORSEPOWER  73 

The  Meaning  of  the  Word  "Rating."— The  rapid- 
ity with  which  this  conversion  of  one  form  of  energy 
into  another  form  may  be  accomplished  is  known  as 
the  rating  of  the  mechanism  involved.  Thus  a  small 
boy  may  by  means  of  a  block  and  tackle  hoist  a  huge 
weight  to  the  top  of  a  modern  sky-scraper  and  at  a 
later  observation  one  may  see  a  team  of  horses  strain- 
ing to  their  utmost  to  accomplish  the  same  task.  By 
close  inspection,  however,  it  will  be  found  that  the 
small  boy  has  by  means  of  intervening  pulleys  been 
able  to  take  from  thirty  to  forty  times  longer  to  ac- 
complish what  the  horses  did  in  a  comparatively  short 
time.  Hence  power,  the  basis  of  comparative  effort, 
is  the  time  rate  of  doing  work. 

The  Development  of  the  Word  "Horsepower." — 
After  his  invention  of  the  steam  engine,  James  Watt 
soon  found  that  he  must  devise  some  unit  or  measuring 
stick,  as  it  were,  with  which  to  measure  the  power  of 
his  mechanism.  As  he  was  a  pioneer  in  the  art,  he  had 
to  cast  about  for  some  convenient  unit  to  adopt.  What 
more  natural  unit  should  he  consider  than  that  of  the 
dra>ft  horse?  After  watching  a  horse  drawing  up 
large  cakes  of  ice  into  an  ice  house  by  the  use  of  a 
snatch  block,  it  occurred  to  him  that  when  the  horse 
pulled  up  a  fairly  good  load  he  must  be  doing  a  cer- 
tain amount  of  work.  After  making  several  experi- 
ments he  found  that  by  adding  more  sheaves  to  the 
blocks  the  horse  could  raise  a  greater  load  but  it  took 
more  time  to  do  it.  He  found  that  the  average  dray 
horse  was  able  to  raise  a  load  of  550  Ibs.  at  the  rate 
of  60  ft.  per  minute,  or  to  do  33,000  ft.  Ibs.  of  work 
per  minute.  This  unit  Watt  called  a  horsepower  and 
applied  it  to  the  measurement  of  the  power  of  his 
steam  engines. 

The  Boiler  Horsepower. — In  the  early  days  of  the 
steam  engine  the  principle  of  the  conservation  of  en- 
ergy had  not  been  firmly  established.  Indeed  that  heat 
was  a  form  of  energy  at  all  was  a  debated  question  for 
many  years  after  the  steam  engine  became  of  vast  prac- 
tical importance. 


74 


FUEL  OIL  AND  STEAM  ENGINEERING 


THE   MECHANICAL   HORSEPOWER 
The   Unit   of  Power  in   Modern   Steam   Engineering 


THE    KILOWATT 

The  Unit  of  Power  in  Electrical  Engineering,   which  is  1.34  times 
the    mechanical    horsepower 


THE    BOILER    HORSEPOWER 

The  Unit   of   Power  in   Boiler  Practice,   which   is    13.14   times   the 
mechanical  horsepower 


THE    MYRIAWATT 

The  Unit  for  Boiler  Rating  Proposed  by  Certain   National  Engi- 
neering  Societies,   which   is   13.4   times   the   mechanical 
horsepower 


BOILER  HORSEPOWER  75 

Hence,  since  the  energy  latent  in  steam  was  not 
then  known  to  be  the  underlying  reason  for  the  power 
driving  action  of  the  steam  engine,  the  first  rating  of 
the  boiler  was  made  on  the  basis  of  power  develop- 
ment in  the  engine  which  received  its  supply  of  steam 
from  the  boiler  in  question.  Thus  a  boiler  that  could 
supply  steam  to  operate  a  steam  engine  developing  50 
indicated  h.p.  was  said  to  be  a  50  h.p.  boiler.  Later  it 
became  evident,  due  to  the  rapidly  increasing 
efficiencies  of  the  steam  engine  that  such  a  rating  was 
wholly  variable.  It  was  found,  however,  that  under 
ordinary  working  conditions  a  boiler  which  could 
evaporate  30  Ib.  of  steam  per  hr.  at  70  Ib.  pressure 
and  taking  feed  water  at  100°  F.  could  usually  operate 
a  1  h.p.  engine,  consequently  this  mode  of  boiler  rating 
became  popular. 

In  1884,  the  American  Society  of  Mechanical  En- 
gineers adopted  the  following  definition  for  the  boiler 
h.p. :  That  a  boiler  evaporating  34.5  Ib.  of  water  at 
212°  F.  into  steam  at  212°  F.  per  hr.  should  be  known 
as  a  1  h.p.  boiler. 

The.  Conversion  qf  Boiler  Horsepower  to  Mechan- 
ical Horsepower  Units. — In  later  years  the  principle 
of  the  conservation  of  energy  finally  became  well  estab- 
lished and  when  engineers  began  to  compute  the 
actual  energy  represented  in  a  mechanical  horsepower 
as  originally  adopted  by  James  Watt  and  then  com- 
pare this  to  the  energy  represented  in  the  steam  gen- 
erated by  what  was  known  as  a  one  horsepower  boiler, 
it  was  found  that  the  boiler  horsepower  represented 
the  conversion  in  unit  time  of  over  thirteen  times  the 
energy  represented  in  the  mechanical  horsepower  unit 
acting  over  the  same  unit  of  time. 

It  is  instructive  to  follow  this  computation  as  it 
will  familiarize  the  reader  with  these  two  distinct 
units.  Let  us  then  proceed  to  an  analysis.  The  me- 
chanical horsepower  unit  is  defined' as  a  performance 
of  work  or  conversion  of  energy  at  the  rate  of  33,000 
ft.  Ib.  per  minute.  Since  1  B.t.u.  of  energy  has  been 
found  to  have  its  equivalent  in  777.5  ft.  Ibs.  of  mechan- 


76  FUEL  OIL  AND  STEAM  ENGINEERING 

ical  work,  it  is  seen  that  33,000  ft.  Ib.  of  work  per  min- 
ute, or  1,980,000  ft.  Ib.  of  work  per  hr.  may  be  repre- 
sented by  2547  B.t.u.  per  hr.  From  the  definition  of 
the  boiler  horsepower  above  mentioned,  as  that 
adopted  by  the  American  Society  of  Mechanical  Engi- 
neers, it  is  seen  that  since  it  requires  970.4  B.t.u.  to 
evaporate  1  Ib.  of  water  at  212°  F.  into  steam  at 
212°  F.,  one  boiler  horsepower  represents  34.5  X  970.4 
B.t.u.  per  hr.  or  33,479  B.t.u.  of  heat  energy  per  hr. 
Hence,  when  we  compare  the  boiler  horsepower  with 
the  ordinary  horsepower  it  is  seen  that  the  boiler 
horsepower  represents  a  unit  which  is  13.14  times 
larger  than  the  ordinary  horsepower. 

The  Myriawatt  as  a  Basis  of  Boiler  Perform- 
ance.— In  recent  years,  due  to  the  tremendous 
growth  in  the  electrical  industry,  engineers  have 
recognized  the  inconsistencies  of  the  boiler  horsepower 
unit  and  an  effort  has  been  made  by  the  national 
engineering  societies  to  make  a  more  rational 
standard  of  rating.  As  a  consequence,  the  American 
Institute  of  Electrical  Engineers  has  proposed  that 
the  Myriawatt  be  adopted  as  a  standard  of  boiler 
rating  instead  of  the  Bl.  h.p.  (A  Myriawatt  is  the 
power  equivalent  of  10,000  watts  or  10  kw.  which 
converted  into  heat  units  become  34,150  B.t.u.  per  hr.) 
Although  it  is  still  to  be  remembered  that  the  Myria- 
\vatt  does  not  yet  make  output  and  input  of  electrical 
units  expressible  in  like  quantities,  since  output  is 
usually  expressed  in  kilowatts,  still  the  factor  of  10 
furnishes  a  basis  readily  convertible  and  makes  pos- 
sible a  change  in  units  without  materially  upsetting 
the  old  boiler  h.p.  range  01  capacity. 

If,  then,  a  -boiler  evaporates  M  pounds  of  steam 
per  hour  .and  the  total  heat  of  each  pound  of  steam  so 
evaporated  be  H  and  the  heat  of  liquid  represented  in 
the  feed  water  be  hf,  then  the  rating  of  a  boiler  in 
Myriawatts  is  evidently 

M  (H  — hf) 

/  Myriawatts  — (1) 

34,150 


BOILER  HORSEPOWER  77 

Relationship  of  Boiler  Horsepower  and  Myria- 
watts. — Similarly,  (  since  one  boiler  horsepower  is 
equivalent  to  heat  absorption  of  33,479  B.t.u,  per  houry 
and  a  myriawatt  to  34,150  B.t.u.  per  hour,  then  we  may 
convert  a  rating-  in  Myriawatts  to  a  rating  in  boiler 
horsepower  or  vice  versa  by  the  relationship : 

Rating  in  boiler  horsepower         34,150 

...(2) 


Rating  in  Myriawatts  33,479 

The  Builder's  Rating. — In  the  commercial  evolu- 
tion of  the  steam  boiler  there  has  grown  up  a  method 
of  rating  boilers  by  "rule  of  thumb"  process.  It  is 
evident  that  the  area  of  the  steam  generating  surface 
of  the  boiler  actually  exposed  to  the  heated  gases  of 
the  furnace  has  something  to  do  with  the  capacity  of 
the  boiler.  For  different  designs  of  boilers,  however, 
the  particular  factor  to  be  applied  varies  widely.  It  has 
become  of  common  acceptance,  however,  that  10  sq.  ft. 
of  boiler  surface  exposed  to  the  furnace  heat  shall  be 
considered  on  this  rule  of  thumb  comparison  as  equiv- 
alent to  one  boiler  horsepower.  Hence  to  compute  the 
builder's  rating  of  a  boiler  we  must  compute  the  area 
in  square  feet  of  the  surface  exposed  to  the  furnace. 
By  dividing  this  area  A  by  ten  we  arrive  at  the  Build- 
er's Rating: 

A 

. '  .  Bl.  h.p.  (Builder's  rating)  = .  (3) 

10 

As  a  detailed  illustration,  let  us  take  the  case  of  a 
Parker  boiler  installed  at  the  Fruitvale  Power  Station 
of  the  Southern  Pacific  Company  in  Oakland,  Cali- 
fornia. 

This  boiler  is  made  up  of  thne  banks  of  tubes  with 
two  drums  above,  half  exposed.  In  detail  we  compute 
as  follows : 

Tubes     4  in.  diameter,  circumference  =  12.566  in.  =  1.0472  ft. 
Tubes  18  ft.  long  — 18  X  1.0472  =18.85  sq.  ft.  of  H.  S. 

Tubes  20  ft.  long  =  20  X  1.0472  =20.94  sq.  ft.  of  H.  S. 


78  FUEL  OIL  AND  STEAM  ENGINEERING 

Heating   Surface,   Bottom   Row   of   Tubes: 

20  tubes  with)  18  ft.  of  Heating  area 

length  exposed  to  gases  =  18.85  X    20  =   377.00  sq.  ft. 

Heatfng  Surface,  First  Pass: 
100  tubes  with  20  ft.  of 

length  -exposed  to  gases  =  20.94  X  100  =  2094.00  sq.  ft. 

Heating  Surface,  Second  Pass: 
80  tubes  with  20  ft.  of 

length  exposed  to  gases  =  20.94  X    80  =  1675.20  sq.  ft. 

Heating  Surface,  Third  Pass: 
80  tubes  with  20  ft.  of 

length  exposed  to  gases  =  20.94  X    80  =  1675.20  sq.  ft. 

Drums : 

2  drums  54  in.  diameter,  18%  ft.  of  length 
exposed  to  gases :  circumference  =  14.1  ft. ; 
V2  of  circumference  7  ft.  =  7x  18.5  X  2  =  259.00  sq.  ft. 

Total    6080.40  sq.  ft. 

Hence,  we  have  that  the  builder's  rating  of  this  boiler 
should  be 

6,080.4 

Bl.  h.p.   (Builder's  rating)  = =  608.04. 

10 

To  Compute  Actual  Boiler  Rating. — Since  it  is 
seen  from  the  fundamental  definition  of  the  boiler 
horsepower  that  the  standard  reference  boiler  gener- 
ates its  steam  from  water  at  212°  F.  into  steam  at 
212°  F.,  we  must  next  develop  a  factor  by  which  we 
can  reduce  ordinary  boiler  performances  of  high  tem- 
peratures and  pressures  to  this  fictitious  standard  be- 
fore we  can  proceed  further.  The  next  chapter  will  be 
devoted  to  this  consideration. 


CHAPTER  IX 

EQUIVALENT   EVAPORATION   AND   FACTOR 
OF  EVAPORATION  IN  FUEL  OIL  PRACTICE 


|N  the  previous  chapter  it 
was  seen  that  as  the  fun- 
damental definition  of  the 
boiler  horsepower  is  based 
upon  a  fictitious  boiler 
that  receives  its  feed 
water  at  212°  F.  and  then 
evaporates  it  into  dry  sat- 
urated steam  at  212°  F. 
and  atmospheric  pressure, 
we  must  now  develop 
some  factor  by  which  we 
can  reduce  boiler  perform- 
ances as  actually  met  with 
in  practice  to  this  fic- 
titious standard. 

In  order  also  to  com- 
pare the  steaming  quali- 
ties of  two  different  boil- 
ers or  indeed  to  compare 
the  same  boiler  under  dif- 
ferent conditions  of  water  supply  and  steam  generation, 
it  is  necessary  that  some  standard  of  comparison  be 
adopted.  Thus  a  boiler  under  its  normal  condition 
of  operation  may  be  found  to  evaporate  13.61  Ib.  of 
water  per  Ib.  of  oil  fired  per  hour  when  taking  its 
feed  water  at  169.1°  F.  and  converting  it  into  super- 
heated steam  at  a  temperature  of  527°  F.  and  a  pressure 
of  185.3  gage.  On  the  other  hand,  the  identical  boiler, 
when  steaming  under  overload  conditions  of  a  feed- 
water  temperature  of  174.1°  F.,  a  superheat  tempera- 


piping     in     Boiler     Setting 
where    Superheat    Tem- 
peratures   are    Taken 


79 


80  FUEL  OIL  AND  STEAM  ENGINEERING 

ture  of  536.9°  F.  and  gage  pressure  of  194.1  Ib.  per 
square  inch  may  be  found  to  evaporate  only  13.17  Ib. 
of  water  per  Ib.  of  oil  fired,  even  though  the  same 
quality  of  oil  be  used  in  each  instance.  It  is  evident 
then  from  sight  that  to  compare  these  two  evaporative 
quantities  without  taking  account  of  the  actual  heat 
transferred  from  the  fuel  to  the  steam  in  the  boiler 
would  be  a  possible  source  of  error. 

The  Standard  that  Has  Been  Adopted. — To  avoid 
inconsistencies  and  to  develop  some  rational  method 
of  comparison,  engineers  have  found  it  convenient  and 
accurate  to  reduce  all  evaporative  quantities  of  a  boiler 
to  a  definite  standard.  In  order  to  follow  out  this 
standardized  comparison,  all  steam  generating  per- 
formances of  boilers  read  as  if  the  boiler  took  its  feed 
water  at  212°  F.  and  atmospheric  pressure,  and  con- 
verted it  into  dry  saturated  steam  at  212°  F.  and  at- 
mospheric pressure,  as  set  forth  in  the  standard  defini- 
tion of  the  boiler  horsepower  in  the  last  chapter.  It  is 
clearly  evident  that  no  such  theoretical  boiler  has  ever 
existed,  yet  this  standard  of  comparison  is  found  very 
convenient.  Thus  in  any  case  of  boiler  performance, 
if  Me  represents  such  an  equivalent  or  comparative 
standardized  evaporation  in  Ibs.  of  water  per  Ib.  of  fuel, 
and  Mw  the  Ib.  of  water  actually  evaporated  in  the  boiler 
under  conditions  of  test,  we  may  now  invent  a  factor 
to  be  known  as  the  factor  of  evaporation,  Fe,  whereby 
such  performances  may  be  readily  reduced : 

M.-MW.    Fe     (1) 

In  the  same  way,  the  equivalent  evaporation  of 
water  per  hour  may  be  computed  from  the  formula 

Meh  =  Mwh.  Fe (2) 

wherein  Meh  and  Mwh  represent  hourly  conditions  of 
evaporation. 

Let  us  next  analyze  the  factor  of  evaporation  and 
see  how  we  may  actually  compute  its  value  for  any 
given  case.  We  have  previously  found  that  in  the 
operation  of  the  boiler,  steam  appears  in  three  differ- 


EQUIVALENT  EVAPORATION  81 

ent  conditions  or  qualities,  namely  in  what  is  known 
as  dry  saturated,  wet  saturated,  or  super-heated  steam. 
Let  us  then  consider  the  evaluation  of  the  factor  of 
evaporation  for  these  three  distinct  instances. 

Dry  Saturated  Steam. — In  the  case  of  dry  satur- 
ated steam,  the  water  enters  the  boiler  already  pos- 
sessing a  heat  of  liquid  hf  corresponding  to  its  en- 
trance temperature  which  may  be  readily  found  in  the 
steam  tables.  This  water  is  next  converted  into  dry 
saturated  steam  which  has  a  total  heat  (He)  corres- 
ponding to  the  pressure  at  which  the  evaporation  takes 
place.  Consequently  the  actual  heat  which  has  been 
transferred  from  the  boiler  shell  to  the  water  is 
(He  —  hf)  heat  units.  But  to  evaporate  one  pound 
of  water  at  212°  F.  into  dry  steam  at  212°  F.  requires 
970.4  heat  units.  Hence  if  Mw  pounds  of  water  are 
evaporated  under  test  conditions,  the  number  of 
pounds  Me  under  standardized  conditions  would  evi- 

(H.-h.) 

dently   be    Mw   — .     Therefore,    for   dry    sat- 

970.4 
urated  steam 

(He  — hf) 

Fe  (dry  saturated  steam)  = (3) 

970.4 

Thus  in  the  case  of  a  boiler  which  takes  its  feed 
water  at  101.8°  F.  and  converts  it  into  dry  saturated 
steam  at  180  Ib.  pressure  per  square  inch,  from  the 
steam  tables  we  find  that  He  is1  1196.4  and  hf  is  69.8, 
hence  the  factor  of  evaporation  is 

H96.4  —  69.8 

Fe  = -=1.16 

970.4 

Wet  Saturated  Steam. — In  the  case  of  wet  sat- 
urated steam  all  of  the  water  entering  the  boiler 
is  not  converted  into  steam.  As  a  consequence  a  cer- 
tain portion  of  heat  (he  —  hf)  is  required  to  raise  the 
temperature  of  the  water  from  entrance  temperature 
tf  to  the  temperature  of  evaporation  te  and  if  only  Xe 


82  FUEL  OIL  AND  STEAM  ENGINEERING 

parts  of  a  lb.  are  then  evaporated  into  steam,  only 
XeLe  B.t.u.  are  required  to  accomplish  this  result. 
Hence,  the  total  heat  required  per  lb.  of  water  so 
evaporated  is  (he  +  Xe  Le  —  hf). 

As  a  consequence  the  factor  of  evaporation  in 
this  case  may  from  similar  reasoning  be  expressed  by 
the  formula 

(he  +  XeLe  —  hf) 

Fe  (dry  saturated  steam)  =  -  -  (4) 

970.4 

As  an  instance  showing  the  application  of  this 
formula  let  us  assume  that  the  boiler  above  men- 
tioned did  not  evaporate  the  water  into  dry  steam  but 
that  upon  investigation  it  was  found  to  contain  5  per 
cent  moisture.  What  now  is  its  factor  of  evaporation? 
From  the  steam  tables  we  find  that  he  is  345.6,  Le  is 
850.8  and  hf  is  69.8.  Therefore  the  factor  of  evapora- 
tion is 

345.6  +  .95X850.8  —  69.8 

Fe  = —1.117 

970.4 

Superheated  Steam. — In  the  third  instance  steam 
is  not  only  evaporated  to  a  dry  saturated  condition, 
but  is  finally  sent  from  the  boiler  in  a  superheated 
condition.  The  steam  tables  are  so  arranged  that  we 
may  find  the  heat  necessary  to  raise  the  total  heat 
of  superheated  steam  when  its  pressure  and  temper- 
ature are  known.  Considering  that  the  water  entered 
the  boiler  at  32°  F.,  let  us  then  call  Hs  the  total  heat 
of  superheated  steam.  Since  now  the  water  entered 
the  boiler  with  a  heat  of  liquid  equal  to  hf  the  actual 
heat  entering  each  lb.  of  steam  evaporated  in  the  boiler 
under  these  conditions  is  (Hs  —  hf)  heat  units.  Hence 
in  this  instance  the  factor  of  evaporation  is  likewise 
from  similar  reasoning  computed  by  the  formula : 
(superheated  steam) 

H.  — h, 

Fe  (superheated  steam)  = (5) 

970.4 


EQUIVALENT  EVAPORATION  83 

To  follow  up  the  same  example  as  set  forth  in  the 
preceding  illustration,  let  us  assume  that  the  steam 
is  evaporated  under  the  conditions  hitherto  mentioned, 
but  that  it  appears  superheated  to  the  extent  of  100°. 
Looking  in  the  steam  tables  we  find  that  the  total 
heat  H8  of  superheated  steam  at  180  Ib.  pressure 
and  100°  superheat  is  1254.3  and  that  the  heat  of  liquid 
hf  is  69.8,  consequently  the  factor  of  evaporation  is 


1254.3  —  69.8 


970.4 


1.22 


To  Compute  the  Boiler  Horsepower.  —  Since  now 
by  means  of  formula  (2),  we  are  enabled  to  compute 
the  equivalent  evaporation  of  Meh  in  pounds  of  water 
per  hour  that  the  boiler  under  test  would  evaporate 
were  it  taking  its  feed  water  at  212°  F.  and  converting 
it  into  dry  saturated  steam  at  the  same  temperature, 
we  can  at  once  compute  the  horsepower  of  the  boiler. 


PLATFORM  SCALES  AND  TANKS  FOR  WATER 

MEASUREMENT 

The  boiler  immediately  to  the  right  of  the  platform  scales  is 
under  test.  The  tank  below  the  platform  scales  into  which 
the  water  is  emptied  after  being  weighed,  is  utilized  to  fur- 
nish all  water  for  the  boiler  during  the  test.  At  the  begin- 
ning of  the  test  a  hooked  gage  registers  the  height  of  the 
water  in  this  tank,  and  at  each  hourly  period  thereafter  suf- 
ficient water  is  weighed  and  emptied  into  it  from  the  tanks 
above  to  maintain  this  exact  level.  By  means  of  these  data, 
properly  taken,  the  factor  of  evaporation  and  the  boiler  horse- 
power are  easily  computed. 


84  FUEL  OIL  AND  STEAM  ENGINEERING 

Under  such  conditions  of  operation  for  every  34.5  Ib. 
of  water  evaporated  per  hour,  the  boiler  is  developing 
one  boiler  horsepower.  Hence  to  compute  the  boiler 
horsepower,  we  write  the  formula : 

Meh 

Bl.  hp.  =  -        - (6) 

34.5 

Thus  if  a  boiler  has  an  equivalent  evaporation  of 
23,350  Ib.  of  water  per  hour,  its  horsepower  is  found 
to  be 

23,350 

Bl.  hp.  = —  676.7 

34.5 

We  could  of  course  develop  an  expression  for  the 
computation  of  boiler  horsepower  by  taking  into 
consideration  the  heat  absorbed  by  the  generation  of 
steam  per  hour.  For  in  our  discussion  in  the  pre- 
vious chapter  it  was  shown  that  one  boiler  horsepower 
is  equivalent  to  the  absorption  of  33,479  heat  units 
per  hour.  Hence,  by  computing  the  heat  absorbed 
by  the  total  pounds  of  steam  generated  per  hour 
and  dividing  this  by  33,479,  we  can  compute  boiler 
horsepower  and  arrive  at  the  same  answer  as  given 
in  the  above  formula.  It  is  better,  however,  for  the 
beginner  to  follow  fundamental  definitions  rather 
than  attempt  too  many  short  cuts  to  gain  quick  re- 
sults. 

In  conclusion  the  important  relationship  to  bear 
in  mind  is  the  vast  difference  between  the  socalled 
mechanical  horsepower  and  the  boiler  horsepower 
which  was  brought  out  in  the  previous  discussion. 
With  this  relationship  firmly  fixed  it  must  be  remem- 
bered that  equivalent  evaporation  is  such. an  evapora- 
tion as  would  be  brought  about  by  taking  in  water 
into  the  boilers  at  212°  F.  and  evaporating  it  into  dry 
saturated  steam  at  212°  F.  and  atmospheric  pressure. 
The  formulas  deduced  above  for  equivalent  evapora- 
tion and  factor  of  evaporation  enable  us  to  do  this. 


CHAPTER  X 


HOW  TO  DETERMINE  QUALITY  OF  STEAM  IN 
FUEL  OIL  PRACTICE 


TEAM  as  used  in  engi- 
neering practice  is  said 
to  be  wet  saturated,  dry 
saturated  or  superheat- 
ed, depending  upon  the 
degree  to  which  heat 
has  been  applied  in  its 
generation. 

Wet  Saturated  Steam 

—As  its  name  implies, 
wet  saturated  steam  is 
saturated  steam  in 
which  are  suspended 
small  globules  or  parti- 
cles of  water.  Since 
such  globules  or  parti- 
cles of  water  indicate 
that  insufficient  heat 
has  been  applied,  and 
consequently  steam 
generation  is  imperfect, 
it  is  the  function  of  all 
good  boilers  to  generate 
steam  as  free  from  water  as  possible. 

Although  steam  be  generated  dry  or  even  super- 
heated it  may,  however,  after  passing  through  con- 
ducting pipes  appear  at  the  power  generating  unit  in 
a  wet  condition.  Hence  the  determination  of  moist- 
ure content  and  the  heat  loss  due  to  its  presence  is  an 
important  one  in  steam  engineering.  • 

Let  us  assume  X  to  be  the  proportion  by  weight 
of  dry  steam  that  exists  in  wet-  saturated  steam.  Then 

85 


Thermometer    Inserted    for 
Superheat  Measurement 


86  FUEL  OIL  AND  STEAM  ENGINEERING 

the  total  heat  represented  in  every  pound  of  such  sat- 
urated steam  at  temperature  t  is 

Ht=  ht  +  XLt    (1) 

This  is  evident  at  once  when  we  consider  that  to  raise 
each  pound  of  original  water  from  32°  F.  to  the  temper- 
ature t,  it  required  ht  heat  units.  On  the  other  hand 
since  a  proportion  by  weight  equal  to  X  has  actually 
gone  into  steam,  the  heat  required  in  the  latent  heat 
of  evaporation  is  but  XLt. 

Dry  Saturated  Steam. — As  one  may  infer  from  the 
heading,  saturated  steam  that  contains  no  moisture  is 
called  dry  saturated  steam.  In  the  chapter  on  prop^ 
erties  of  water  the  determination  of  its  total  heat  was 
illustrated  quite  fully.  We  may,  however,  derive  the 
equation  for  total  heat  of  dry  saturated  steam  from 
the  equation  above  for  wet  saturated  steam.  For  in 
this  latter  instance  since  no  water  is  present,  evidently 

X  becomes  equal  to  unity.  Hence  for  dry  saturated 
steam 

Ht  =  ht  +  Lt (2) 

Superheated  Steam. — It  has  been  hitherto  pointed 
out  that  when  water  is  being  evaporated  into  steam  the 
temperature  remains  constant  until  all  the  water  dis- 
appears. So  long,  however,  as  steam  remains  in  con- 
tact with  the  water  from  which  it  is  being  formed  it 
is  either  dry  or  wet  saturated  steam  and  its  tempera- 
ture cannot  be  raised  above  that  which  normally  rep- 
resents the  boiling  point  of  water  for  the  pressure 
under  which  the  steam  is  being  generated. 

It  has,  however,  been  found  of  immense  economic 
value  in  steam  engineering  practice  to  actually  use 
steam  that  is  heated  over  a  hundred  degrees  in  excess 
of  the  temperature  at  which  saturated  steam  may  be 
generated  under  the  existing  pressure  conditions.  It 
is  seen  that  such  steam  must,  of  course,  first  become 
absolutely  dry  and  then  any  additional  heat  that  may 
be  added  goes  toward  raising  its  temperature  if  the 
pressure  be  kept  constant. 

This  is  accomplished  in  the  modern  steam  gener- 
ating units  by  conducting  the  saturated  steam  from 


QUALITY  OF  STEAM  87 

the  main  drums  in  which  it  is  generated  and  passing 
it  through  pipes  exposed  to  highly  heated  portions  of 
the  boiler  furnace.  Such  a  system  of  pipes  is  known 
as  a  superheater.  The  steam  quickly  absorbs  sufficient 
heat  to  completely  dry  it  and  still  further  raise  its  tem- 
perature. 

Computation  of  Total  Heat  of  Superheated  Steam. 

• — If  a  definite  constant  quantity  of  heat  were  required 
to  superheat  a  pound  of  steam  one  degree  in  tempera- 
ture for  all  ranges  of  temperature  and  pressure,  we 
could  write  down  a  comparatively  simple  formula  for 
arriving  at  the  total  heat  of  superheated  steam.  Since, 
however,  this  specific  heat  constant  has  a  wide  range 
of  .46  to  .60  it  is  impossible  to  do  so. 

Hence  in  each  case  of  temperature,  pressure  and 
degree  of  superheat,  we  must  refer  to  steam  tables  in 
order  to  find  the  proper  value  of  total  heat  of  super- 
heated steam.  And,  indeed,  this  too  is  necessary  to 
find  all  the  other  constants  that  relate  to  superheated 
steam. 

The  fundamental  definition  remains  the  same,  how- 
ever— namely  that  the  quantity  of  steam  required  to 
raise  one  pound  of  water  from  32°  F.  to  the  tempera- 
ture t  corresponding  to  the  boiling  point  of  water  for 
the  pressure  at  which  the  steam  is  generated,  added 
to  the  latent  heat  of  evaporation  for  this  pressure,  to- 
gether with  such  additional  heat  as  may  be  required  to 
raise  the  one  pound  of  now  dry  saturated  steam  to  the 
degree  of  superheat  given,  is  known  as  the(total  heat 
of  superheated  steam  i  Hs.  Expressing  this  algebra- 
ically we  have 

Hs  =  ht  +  Lt  +  Cpm  (t.  —  t)  (3) 

As  an  example  let  us  suppose  that  superheated 
steam  is  being  generated  at  ordinary  atmospheric  pres- 
sure and  delivered  at  a  temperature  of  312°  F.  We  will 
suppose  that  the  mean  specific  heat  Cpm  for  the  range 
of  temperature  and  pressure  under  consideration  is 
say  0.46.  Then  from  the  tables,  we  find 

ht  =  180.       Lt  =  970.4.     t.  =  312°. 


88 


FUEL  OIL  AND  STEAM  ENGINEERING 


t  =  212°.     Cpm=       .46 
. ' .  Hs  —  180  +  970.4  +  .46  (312  —  212) 

=  180  +  970.4  +  46  =  1196.4  B.tu, 

It  is  most  important  that  the  student  should  re- 
member that  although  the  value  Hs  may  be  taken 
directly  from  the  steam  tables,  still  it  is  based  on  the 
several  steps  above  taken.  In  many  steam  engineering 
problems  this  separate  analysis  or  dissecting  must  be 
done  so  it  is  well  to  clinch  this  matter  without  delay. 

Steam  Calorimeters. — The  word  calorimeter  often 
causes  considerable  confusion  because  there  are  two 
entirely  different  and  distinct  types  of  mechanism  that 
bear  this  name  in  engineering  practice.  Fundamen- 
tally it  means  "a  measurer  of  heat."  In  order  to  deter- 
mine the  heat  contained  in  fuel  an  instrument  known 
as  a  calorimeter  is  employed  which  will  be  described 
in  later  pages.  At  this  point,  however,  we  shall  now 
proceed  to  describe  several  types  of  an  instrument 


TEMPERATURE     DETERMINATION      FOR     SUPERHEATED 
STEAM 

In  taking:  the  temperature  for  superheated  steam  a  thermometer 
should  be  inserted  as  near  the  superheated  drum  as  practicable. 
The  thermometer  has  suspended  at  its  side  a  second  thermometer 
in  order  to  ascertain  the  proper  correction  to  be  made  for  that 
portion  emerging  from  the  bath  in  which  the  main  thermometer 
rests  so  that  the  stem  correction  may  be  made.  In  the  illustration 
may  be  seen  the  point  at  which  the  thermometer  well  for  ascer- 
taining the  superheated  steam  temperature  was  inserted  in  finding 
the  superheat  for  an  installation  in  Oakland,  California. 


QUALITY  OF  STEAM  89 

that  bears  the  same  name  and  yet  is  entirely  differ- 
ent both  in  design  and  in  aim  to  be  accomplished. 

The  steam  calorimeter  is  an  instrument  used  in 
steam  engineering  practice  to  determine  the  exact 
quality  of  steam,  whether  it  be  wet  saturated,  dry 
saturated,  or  superheated,  and  to  what  extent.  Since 
the  thermometer  and  the  carefully  calibrated  pressure 
gage  constitute  the  easiest  and  most  direct  method  of 
ascertaining  superheat,  the  uses  of  the  steam  calori- 
meter are  usually  limited  to  determination  of  mois- 
ture in  wet  saturated  steam. 

The  Determination  of  Superheat. — The  method  of 
ascertaining  superheat  will  now  be  set  forth. 

A  thermometer  is  inserted  in  the  outlet  of  the  su- 
perheater drum,  and  the  temperature  read,  and  at  the 
same  instant  the  pressure  of  the  superheater  drum 
is  read  on  a  steam  gage  attached  to  this  drum.  If  now 
the  thermometer  reads  539°  F.  and  the  steam  gage 
reads  178.5  Ib.  per  sq.  in.  and  the  atmospheric  pres- 
sure is  14.7  Ib.  per  sq.  in.,  we  proceed  as  follows : 

The  absolute  pressure  of  the  superheated  steam  is 
the  sum  of  178.5  and  14.7  which  is  193.2  Ib.  per  sq.  in. 
Referring  to  steam  tables,  we  find  that  water  boils, 
or  rather  saturated  steam  is  generated,  at  a  temperature 
of  379°  F.  when  under  a  pressure  of  193.2  Ib.  per  sq.  in. 
Hence,  the  superheat  of  the  steam  under  consideration 
is  the  difference  of  539°  and  379°,  which  is  160°  F. 

Determination  of  Moisture  in  Saturated  Steam. — 
There  are  many  methods  that  may  be  used  in  deter- 
mining the  moisture  content  of  saturated  steam.  The 
particular  method  to  be  employed  depends  much  upon 
the  accuracy  desired  and  the  degree  or  intensity  of  the 
moisture  content  present. 

The  Barrel  or  Tank  Calorimeter. — In  this  method, 
which  should  never  be  used  except  for  approximate 
results,  the  steam  is  allowed  to  pass  up  through  a  bar- 
rel of  water.  Of  course,  the  steam  at  once  condenses 
into  water  and  the  resulting  mixture  with  the  water  in 
the  barrel  raises  the  temperature.  By  taking  the  pres- 
sure of  the  steam  and  the  two  temperatures  of  the 


90  FUEL  OIL  AND  STEAM  ENGINEERING 

water  —  the  one  before  applying  the  steam  and  the 
other  after  its  application  together  with  the  weights 
of  the  water  involved,  we  may  at  once  write  a  math- 
ematical relationship  to  determine  the  moisture  con- 
tent. 

If  we  neglect  radiation  and  other  stray  losses,  the 
heat  gained  by  the  water  in  the  barrel  is  equal  to  that 
lost  by  the  steam  under  test. 

In  all  the  subsequent  discussions  in  this  chapter 
let  us  let  0  subscripts  represent  conditions  of  steam  in 
the  boiler;  1  subscripts,  the  initial  conditions  in  the 
barrel;  2  subscripts,  the  final  conditions  in  the  barrel; 
and  W  will  represent  the  weights  involved. 

The  total  heat  of  each  pound  of  entering  steam 
is  by  equation  (1)  found  to  be  (h0  -f-  X0L0)  and  since 
after  this  pound  of  condensed  steam  mixes  with  the 
water  in  the  barrel  it  still  has  h2  units  of  heat,  there 
is  then  a  net  loss  of  (h0  -\-  X0  L0  —  h2)  heat  units.  In 
the  same  way  each  pound  of  water  in  the  barrel  gains 
(h2  —  ht)  heat  units.  If  W0  units  of  steam  are  in- 
volved and  W±  units  of  water  are  found  in  the  barrel 
at  the  beginning  of  the  test,  we  know  then,  since 
heat  lost  by  the  steam  is  equal  to  heat  gained  by  the 
water,  neglecting  radiation  and  other  losses,  that 

W0    (h0  +  X0L0  —  h2)=W1    (h2  —  hO 


WL 


(4) 


As  an  example,  it  was  found  in  a  test  that  a  steam 
main  under  90  Ib.  pressure  (gage)  deposited  3  Ib.  of 
condensed  steam  "into  a  vessel  that  contained  27  Ib.  of 
water  at  62°  F.,  thereby  raising  the  temperature  to 
175°  F.  We  compute  the  proportion  of  dry  steam  in 
the  main  as  follows  : 

P0  =  90  Ib.  per  sq.  in.  (gage)  =  104.7  Ib.  per  sq.  in.  abs, 

Wi  =  27  Ib.,  W0  =  3  Ib.    tt  =  62°  F.,  t2  =  175°  F. 
Hence  from  steam  tables  — 

L0=:  885.4,  h0  -=301.8,  ^  =  30.1,  h2  =  142.9. 


QUALITY  OF  STEAM  91 

27  (142.9  —  30.1  )  —  3  (301.8  —  142  .9) 
.    .  X0  =  -  --  —.968 
3  X  885.4 

.  '  .  X0  —  96.8%  dry  steam  in  steam  under  test. 

Surface  Condenser  Tank  Calorimeter.  —  This 
method  varies  from  the  one  just  set  forth  in  that  the 
condensed  steam  does  not  mingle  with  the  water  in 
the  barrel.  To  accomplish  this  the  steam  is  passed 
through  a  coil  of  piping  which  is  inserted  in  the  tank. 
As  the  steam  comes  in  contact  with  the  cooling  surface 
of  this  pipe,  it  is  condensed  into  water  and  of  course 
the  heat  thus  liberated  or  given  out  is  absorbed  by  the 
water  in  the  tank  and  its  temperature  correspondingly 
raised.  Hence  in  this  instance,  it  is  necessary  to 
weigh  the  water  in  the  tank  and  the  condensed  steam 
discharged  through  the  coil.  It  is  also  necessary  to 
take  the  pressure  of  the  steam  under  observation  and 
to  note  the  temperature  of  the  tank  water  before  and 
after  application  as  well  as  the  temperature  of  the 
water  discharged  from  the  coils. 

Proceeding  by  similar  reasoning  as  set  forth  in 
the  former  instance,  the  heat  lost  by  each  pound  of 
steam  is  sure  to  be  (h0  +  X0  L0  —  h3),  wherein  the 
subscript  3  is  to  denote  the  condition  of  the  steam 
condensed  into  water  as  it  emerges  from  the  coil.  The 
heat  gained  by  each  pound  of  water  in  the  tank  is  also 
seen  to  be  (h2  —  hj  heat  units.  Hence  if  W0  lb.  of 
condensed  steam  are  discharged  and  Wx  lb.  of  water 
are  found  in  the  tank,  since  the  heat  lost  by  the  steam 
is  equal  to  that  gained  by  the  water,  neglecting  radia- 
tion and  other  minor  losses,  we  have 


W0  (X0  L0  +  h0  _  hs)  =  W±  (h2  —  hj 

W^h,  —  hj—  W0(h0  —  hj 

•  '.  Xo  =  -  - 

WL 


(5) 


00 


To  illustrate,  let  us  assume  that  one  pound  of 
steam  at  a  pressure  of  100  lb.  per  sq.  in.  absolute  is 
passed  through  coils  immersed  in  a  tank  containing  ten 


92  FUEL  OIL  AND  STEAM  ENGINEERING 

pounds  of  water  at  an  initial  temperature  of  100°  F. 
At  the  conclusion  of  the  condensation  the  water  in  the 
tank  is  found  to  be  at  a  temperature  of  204.5°  F., 
while  that  emerging  from  the  coils  is  210°  F.  The 
quality  of  the  steam  is  at  once  found  by  substitution 
in  the  formula  as  follows : 

From  the  test  data  we  have  p0  =  100  lb.,  W±  = 
10  lb.,  W0  =  l  lb.,  t1  =  1008  F.,  ta  =  204.5°  F,  and 
t3=:210°  F.  From  the  steam  tables,  we  find  h1==68, 
h2=  172.5,  h3  =  178,  h0 -=298.3,  L0  =  888.0. 

10  (172.5  —  68)  —1  (298.3  —  178) 

.•.X0=  —  =1.05 

1  X888 

Since  the  quality  of  steam  is  greater  than  unity, 
it  is  evident  that  the  steam  in  this  instance  is  super- 
heated. 

The  principle  upon  which  the  more  accurate  steam 
calorimeters  operate  is  in  general  accomplished  along 
similar  lines.  We  shall,  however,  reserve  further  dis- 
cussion on  the  subject  un,til  the  next  chapter  wherein 
we  shall  deal  at  length  with  these  calorimeters. 


CHAPTER  XI 


THE  STEAM  CALORIMETER  AND  ITS  USE  IN 
FUEL  OIL  PRACTICE 

We  come  now  to  a  consideration  of  the  methods 
used  in  steam  engineering  practice  to  accurately  de- 
termine the  moisture  content  of  saturated  steam.  In 
the  preceding  chapter  certain  approximate  methods 
were  set  forth,  but  in  the  following  discussion  it  will 
be  seen  that  by  care  and  patience  the  moisture  con- 


Thermometer 


THE  THROTTLING  CALORIMETER  AND  THE  SAMPLING 
NOZZLE 

In  the  typical  throttling  calorimeter,  steam  is  drawn  from  a  verti- 
cal main  through  the  sampling  nipple,  then  passed  around  the 
first  thermometer  cup,  then  through  a  one-eighth  inch  orifice  in  a 
disk  between  two  flanges,  and  lastly  around  the  second  thermometer 
cup  and  to  the  atmosphere.  Thermometers  are  inserted  in  the 
*vells,  which  should  be  filled  with  mercury  or  heavy  cylinder  oil. 
Due  to  the  fact  that  the  heat  content  in  the  steam  under  the  ex- 
panded condition  with  which  it  reaches  the  second  thermometer,  is 
much  less,  the  heat  thus  liberated  superheats  the  steam  at  this 
point  and  thus  a  means  is  given  for  ascertaining  the  moisture  or- 
iginally in  the  steam  sample. 

tent  of  saturated  steam  may  be  ascertained  with  a 
wonderful  degree  of  accuracy. 

93 


94  FUEL  OIL  AND  STEAM  ENGINEERING 

The  Chemical  Calorimeter. — The  chemist  has  a 
method  of  determining  the  moisture  content  which 
finds  little  application  in  the  steam  engineering  labo- 
ratory, but  in  the  chemist's  laboratory  it  is  performed 
with  a  remarkable  degree  of  accuracy.  Certain  salts 
absorb  moisture  held  in  a  vapor.  Hence  by  passing 
wet  saturated  steam  over  such  salts,  the  moisture 
content  is  taken  from  the  steam  and  by  weighing  the 
moisture  so  absorbed  the  degree  of  moisture  held  in 
suspension  is  ascertained. 

The  Throttling  Calorimeter.  —  By  reference  to 
the  steam  tables  it  is  seen  that  when  saturated  steam 
exists  at  say  200  Ib.  pressure  per  sq.  in.,  each  pound 
of  steam  represents  a  storage  of  heat  equal  to  1197.6 
B.t.u.  For  it  is  seen  from  the  steam  tables  that  it 
took  354.4  B.t.u.  to  bring  the  original  pound  of  water 
from  32°  F.  to  its  boiling  point  and  then  an  additional 
843.2  B.t.u.  to  evaporate  this  water  into  dry  satu- 
rated steam. 

Let  us  suppose  for  a  minute  this  steam  at  200  Ib. 
per  sq.  in.  were  allowed  to  flow  through  an  orifice  and 
expand  into  a  chamber  which  was  at  but  14.7  Ib.  per 
sq.  in  From  the  steam  tables  it  is  seen  that  saturated 
steam  existing  under  such  a  pressure  holds  in  storage 
but  1150.4  B.t.u.  What  then  becomes  of  the  difference 
between  1197.6  B.t.u.  and  1150  B.t.u.  represented  by 
the  heat  held  in  storage  in  the  two  instances?  Evi- 
rteiuJy  if  the  main  at  the  lower  temperature  be  well 
hooded  so  that  no  heat  escapes,  the  heat  given  out 
must  go  toward  superheating  the  steam  at  the  lower 
pressure.  Since  the  specific  heat  of  superheated 
steam  at  the  lower  pressure  is  about  .47  the  47.2 
B.t.u.  that  are  liberated  would  evidently  superheat 
the  steam  about  100°.  The  actual  measurement,  then, 
of  this  superheat  gives  us  at  once  a  most  accurate 
method  of  determining  the  quantity  of  moisture  present 
in  the  steam  at  the  original  pressure.  For  if  we  find 
that  the  steam  is  superheated  only  25°  F.,  instead  of 
100°  F.,  evidently  some  of  the  mixture  must  have 
been  water,  for  otherwise  its  existence  at  the  higher 


THE  STEAM  CALORIMETER 


95 


temperature  as  steam  would  aid  in  superheating  still 
further  the  lower  temperature. 

A  throttling  calorimeter,  then,  is  simply  a  con- 
trivance by  which  we  allow  steam  to  pass  from  its 
high  pressure  through  a  small  opening  where  its  tem- 


THE  SEPARATING  CALORIMETER 

In  this  type  of  separating  calorimeter  the  steam,  with  its  moisture 
enters  from  the  steam  main  at  6  and  is  forced  to  travel  downward 
toward  3  at  a  high  velocity.  At  14,  however,  the  direction  is  sud- 
denly reversed  upward  toward  7  and  later  passes  downward  through 
4  and  out  into  the  atmosphere  at  8.  When  the  sudden  reversal 
takes  place  at  14,  the  moisture  in  the  steam  collects  at  3  and  its 
content  is  measured  on  the  gage  12.  The  steam  content,  on  the 
other  hand,  is  calculated  by  means  of  Napier's  formula  as  it  passes 
through  the  orifice  at  8  as  illustrated  in  the  text. 

perature  and  pressure  are  taken  before  it  passes  out 
into  the  atmosphere.  Prior  to  its  passage  through 
the  small  opening,  the  temperature  and  pressure  of 
the  steam  is  noted.  Let  us  denote  by  "s"  subscripts 
the  conditions  of  superheated  steam  in  the  low  pres- 
sure chamber,  "o"  subscripts  the  steam  in  the  steam 
main,  and  "3"  subscripts  saturated  steam  at  the  pres- 
sure of  the  low  pressure  chamber. 

Each  pound  of  wet  saturated  steam  in  the  steam 
main  has  X0  parts  by  weight  existing  as  dry  steam.' 
Hence  the  total  heat  represented  in  each  pound  of  this 


96  FUEL  OIL  AND  STEAM  ENGINEERING 

steam  is  evidently  (X0  L0  +  h0)  heat  units  as  seen 
from  close  inspection.  In  the  same  manner  each  pound 
of  steam  in  the  lower  pressure  chamber  holds  in  stor- 
age [H3  -|-  Cpm  (ts  —  t3)]  heat  units  as  seen  from  pre- 
vious reasoning.  Since  no  heat  is  allowed  to  escape,  evi- 
dently these  expressions  are  equal  one  to  the  other,  or 

X0  L0  +  h0  ==  H3  +  Cpm  (t.  — 13) 

Cpm  for  the  low  pressures  has  a  value  of  0.47,  hence,  we 
have 

H3  +  0.47  (t.  —  ts)  —  h0        Hs  —  h0 
X0  =  -  ....(1) 

L0  L0 

in  which  Hs  is  the  total  heat  of  superheated  steam  in 
the  low  pressure  chamber.  Its  numerical  value  may 
be  taken  directly  from  the  steam  tables  when  the 
pressure  and  degree  of  superheat  are  known. 

As  an  illustration,  let  us  assume  that  the  pressure 
in  the  steam  main  is  153.6  lb..  per  sq.  in.  abs.  and  that 
its  temperature  is  found  to  be  362.9°  F.,  thus  indi- 
cating at  once  that  the  steam  is  saturated  and  not  su- 
perheated. After  it  has  expanded  into  the  low  pres- 
sure chamber  it  is  found  to  have  a  temperature  of 
261.3°  F.  and  a  pressure  of  14.8  lb.  per  sq.  in.  absolute. 

From  the  steam  tables  we  find  L0  =  859.6; 
h0  =  334.8 ;  H3  =  1150.5  ;  t.  =  261.3 ;  t3  =  212.4°  F, 

1150.5  —  334.8  —  .47  (261.3  —  212.4) 

.-.X0  = ^  =  .9758 

859.6 

Therefore  the  steam  is  evidently  97.58  per  cent  dry. 
The  Limitations  of  the  Throttling  Calorimeter. — A 

little  consideration  of  the  underlying  principle  of  the 
throttling  calorimeter  brings  to  light  a  definite  range 
of  limitation  to  its  usefulness.  It  will  be  remembered 
that  this  fundamental  principle  consists  in  liberating 
sufficient  heat  at  the  lower  pressure  not  only  to 
evaporate  any  moisture  that  may  exist  but  to  actually 
superheat  the  entire  mixture.  If  there  is  not  suffi- 
cient heat  liberated,  that  is  if  too  much  water  is  held 
in  suspension  in  the  saturated  steam,  the  steam  at  the 


THE  STEAM  CALORIMETER  9? 

lower  pressure  fails  to  become  superheated  and  hence 
we  have  no  means  of  measurement. 

Thus  if  steam  pass  from  100  Ib.  absolute  pressure 
per  sq^  in.  to  30  Ib.  absolute  pressure  per  sq.  in.,  the 
total  heat  at  the  upper  pressure  is  (X0  L0  -|-  h0)  which 
from  the  steam  tables  becomes  (X0888  +  298.3)  heat 
units  and  that  at  the  lower  pressure  is  H3,  or  1163.9, 
if  it  be  not  at  all  superheated.  Hence  we  have 

X0  888 +  298.3  =  1163.9 

865.6 

. ' .  X0  = =  .9748 

888 

This  means  that  if  there  is  a  greater  moisture  content 
than  2.52  per  cent  the  steam  calorimeter  will  fail  to 
work  because  the  mixture  in  the  lower  pressure  space 
does  not  become  superheated. 

If  instead  of  having  the  low  pressure  of  30  Ib. 
absolute  per  square  inch,  the  steam  in  the  calorimeter 
had  been  throttled  down  to  14.7  Ib.  the  value  of  H3 
would  have  been  1150.4  instead  of  1163.9  so  that  X0 
would  become  .9597  and  the  limit  of  the  calorimeter 
in  this  case  would  be  4.03  per  cent  of  moisture. 

Again  if  instead  of  steam  at  100  Ib.  absolute  pres- 
sure we  had  steam  at  200  Ib.  and  allowed  the  sample 
in  the  calorimeter  to  be  throttled  down  to  14.7  Ib.  it 
may  be  found  in  the  same  way  that  the  limit  of  the 
calorimeter  is  5.66  per  cent  of  moisture.  It  is  thus 
seen  that  the  greater  the  difference  in  pressure  be- 
tween the  high  pressure  and  the  low  pressure  in  the 
calorimeter,  the  greater  is  the  range  of  the  calori- 
meter. 

The  Electric  Calorimeter. — It  is  now  evident  that 
if  a  definitely  measurable  quantity  of  heat  could  be 
added  to  the  steam  before  it  was  allowed  to  expand, 
even  very  wet  steam  might  be  accurately  measured 
by  the  throttling  calorimeter.  This  is  seen  at  once 
when  we  analyze  the  total  heats  involved.  If  E0 
be  the  heat  units  added  to  each  pound  of  steam,  then 
the  total  heat  possessed  by  each  pound  of  steam  in 


98  FUEL  OIL  AND  STEAM  ENGINEERING 

the  high  pressure  main  is  (X0  Lto  +  no  +E0)  heat  units 
and  since  the  heat  in  each  pound  of  steam  in  the  lower 
chamber  is  Hs,  we  have,  since  no  heat  escapes 

X0  L0  +  h0  +  E0  =  Hs 
TT          Vi         F 

J-J-s  110  -L^o 

• '  •  X0  = .    (2) 

L0 

In  the  Thomas  electric  meter  an  electrical  me- 
chansim  has  been  invented  whereby  a  series  of  small 
wires  electrically  heated  impart  a  known  quantity  of 
electrical  energy  to  the  steam.  This  electrical  energy 
dissipates  itself  as  heat  and  since  we  can  transfer 
electrical  units  into  heat  units  and  vice  versa,  a  ready 
means  is  provided  to  assist  the  throttling  calorimeter 
in  doing  its  work  by  adding  sufficient  heat  to  widen 
the  range  of  the  throttling  process. 

Thus,  although  the  throttling  calorimeter  was 
found  definitely  limited  above  as  set  forth,  let  us  in- 
vestigate a  case  where  the  electrical  calorimeter  may 
be  used.  Let  us  assume  the  upper  pressure  to  be  200 
Ib.  per  sq.  in.  and  the  lower  pressure  15.0  Ib.  per  sq. 
in.  In  this  case  there  were  electrically  added  exactly 
40  B.t.u.  of  energy  and  the  temperature  of  superheat 
ts  was  found  to  be  233.0°  F.,  hence  from  the  steam 
tables  we  find 

L°  =  843.2  ;  h0  =  354.9;  ts  =  233.0;  hence,  HB=  1160.1 
1160.1  —  354.9  —  40 


=  0.908 


843.2 

The  Separating  Calorimeter. — In  the  separating 
calorimeter  the  moisture  is  mechanically  separated 
from  the  steam.  If  we  know  the  total  amount  of  steam 
passing  and  also  the  weight  of  the  water  separated 
from  the  steam,  it  is  of  course  an  easy  problem  to 
compute  the  dryness  of  the  steam.  Thus,  if  W\  is 
the  weight  of  water  separated  per  hour  in  the  calori- 
meter and  W2  the  weight  of  dry  steam  passing  out  of 
the  calorimeter  per  hour,  we  have  by  inspection 


THE  STEAM  CALORIMETER  99 

W2 

X.  = (3) 

W,  +  W, 

Hence,  if  a  separating  calorimeter  deposits  285  Ib.  of 
water  per  hour  and  if  10,000  Ib.  of  dry  saturated  steam 
leave  the  calorimeter  per  hour,  the  dryness  of  the 
steam  is 

10000 

X0—  -  =  0.972 

10000  +  285 

There  are  many  principles  upon  which  the  sepa- 
rating calorimeter  may  operate.  There  are  two  forms, 
however,  which  are  more  usual  than  others.  In  one 
instance  the  steam  mixture  is  given  a  rotary  motion 
in  its  journey  and  consequently  the  water  particles 
are  thrown  off  by  centrifugal  force  and  collect  in  a 
drip  below.  In  the  other  instance  the  stream  flow 
receives  a  sudden  reversal  in  direction.  As  dry  steam 
easily  performs  this  feat  and  water  insists  upon  con- 
tinuing its  former  direction  of  flow  a  separation  is 
thus  mechanically  effected. 

This  type  of  instrument  is  not  as  accurate  as  the 
throttling  type,  as  it  does  not  get  all  the  moisture  out 
of  the  steam.  When  large  quantities  of  moisture  are 
present,  however,  it  proves  useful  in  taking  out  the 
bulk  of  the  water  or  moisture  while  a  throttling  cal- 
orimeter connected  in  series  later  on  accurately  meas- 
ures the  remaining  water  content  present.  Thus  by 
such  a  method  of  operation  any  degree  of  moisture 
present  in  steam  is  easily  and  accurately  measured. 

Correction  for  Steam  Used  by  Calorimeter. — In  a 

great  many  instances  the  total  weight  of  steam  passing 
per  hour  through  the  steam  main  under  test  is  of  prime 
importance.  Since  most  forms  of  calorimeter  operate 
by  diverting  a  portion  of  this  steam  out  into  the  at- 
mosphere, it  becomes  necessary  to  have  some  quick 
and  ready  means  of  computing  the  quantity  of  steam 
so  diverted. 


100  FUEL  OIL  AND  STEAM  ENGINEERING 

Many  years  ago  Napier  deduced  an  approximate 
formula  for  the  flow  of  steam  into  the  atmosphere  from 
a  high  pressure  source.  This  formula  is  well  within 
the  degree  of  accuracy  required  for  steam  diverted 
through  the  calorimeter.  If  W  is  the  pounds  of  steam 
flowing  per  second,  p  the  pounds  of  pressure  per  square 
inch  exerted  'by  the  steam  in  the  main,  and  a  the  area 
of  the  orifice  in  square  inches  through  which  the  steam 
passes,  then 

pa 
W  = (4) 

70 

The  Sampling  Nipple. — The  American  Society  of 
Mechanical  Engineers  recommends  a  sampling  nipple 
made  of  one-half  inch  iron  pipe  closed  at  the  inner  end 
and  the  interior  portion  perforated  with  not  less  than 
twenty  one-eighth  inch  holes  equally  distributed  from 
end  to  end  and  preferably  drilled  in  irregular  or  spiral 
rows  with  the  first  hole  not  less  than  one-half  inch 
from  the  wall  of  the  pipe.  (The  failure  to  determine  an 
average  sample  of  the  steam  is  the  principal  source  of 
error  in  steam  calorimeter  determinations.  "> 

Conclusions  on  Moisture  Measuring  Apparatus. — 
Summing  up  the  arguments  of  this  chapter  we  see  that 
for  comparatively  small  quantities  of  moisture  present 
in  steam,  the  throttling  calorimeter  is  the  most  accurate 
device  for  its  quantitative  determination.  If,  however, 
large  quantities  of  moisture  are  present,  two  methods 
present  themselves.  Either  we  must  first  remove  the 
major  portion  of  the  moisture  by  means  of  a  sepa- 
rating calorimeter  and  later  determine  the  remaining 
moisture  content  by  means  of  the  throttling  calori- 
meter, or  we  must  add  a  definite  quantity  of  heat  to 
the  original  steam  supply  by  means  of  a  device  such 
as  the  Thomas  Electric  calorimeter  and  then  deter- 
mine with  proper  computation  factors  the  moisture 
present  by  means  of  the  throttling  calorimeter. 

As  already  shown  the  throttling  calorimeter  may 
be  used  up  to  moisture  of  4  per  cent  for  steam  at  100 


THE  STEAM  CALORIMETER 


IQ1 


lb.  pressure  and  up  to  a  lit- 
tle over  5  per  cent  for 
steam  at  200  lb.  pressure. 
Most  boilers  deliver  steam 
containing  not  more  than 
\y2  per  cent  or  2  per  cent 
of  moisture  so  that  for  near- 
ly all  ordinary  work  the 
throttling  calorimeter  has 
sufficient  range,  and  owing 
to  its  great  simplicity  and 
remarkable  accuracy  it  is 
almost  universally  used. 
It  is  possible  to  make  up  a 
throttling  calorimeter  by 
means  of  pipe  fittings  by 
providing  a  disc  within  a 
pair  of  flanges  having  a 
small  hole  to  act  as  the 

A  Suggestion  for  a  Convenient 

and  compact  Type  of  Throt-  throttling    agent ;    or    the 

throttling  may  be  done 
merely  by  partially  opening 

the  valve  on  the  sampling  nipple  close  to  the  main  steam 
pipe.  An  extremely  convenient  design  of  calorimeter 
and  one  that  can  be  readily  moved  from  place  to  place 
is  shown  in  the  illustration.  In  this  design  a  steam 
jacket  is  provided  to  prevent,  as  far  as  possible  radia- 
tion losses  from  the  calorimeter.  For  many  further 
useful  pointers  and  detail  rules  in  ascertaining  the 
moisture  content  of  steam  the  reader  is  referred  to  the 
latest  edition  of  "Steam"  .by  the  Babcock  &  Wilcox 
Company,  and  to  the  report  of  the  Power  Test 
Committee  of  the  American  Society  of  Mechanical 
Engineers  which  is  to  be  found  in  Vol.  37,  transactions 
A.  S.  M.  E.  for  1915,  to  which  publications  we  are 
indebted  for  much  of  the  information  contained  in 
this  discussion. 


CHAPTER  XII 

RATIONAL  AND  EMPIRICAL  FORMULAS  FOR 

STEAM  CONSTANTS  IN  FUEL  OIL 

PRACTICE 

It  has  hitherto  been  pointed  out  that  the  relation- 
ships of  temperature,  latent  heat  and  other  steam  prop- 
erties are  so  complicated  with  varying  pressures  that 
no  one  as  yet  has  been  able  to  set  forth  simple  mathe- 
matical equations  for  their  representation. 

There  exist,  however,  a  vast  number  of  more  or 
less  complicated  formulas  that  express  with  some  de- 
gree of  accuracy  a  relationship  between  these  vari- 
ous factors.  When  such  a  relationship  is  deduced 
from  some  process  of  reasoning  based  upon  known 
laws  the  equation  is  said  to  be  rational.  If,  on  the 
other  hand,  some  one  by  sifting  through  the  sands  of 
time,  as  it  were,  has  happened  upon  an  equation  with 
no  rational  backing  the  formula  is  said  to  be  em- 
pirical. 

Most  of  the  equations  used  to  set  forth  steam 
variables  are  party  rational  and  partly  empirical. 

Any  equation,  unless  it  be  comparatively  simple, 
is  of  little  practical  use  to  the  steam  engineer,  for  he 
may  pick  the  values  desired  from  the  modern  steam 
tables  with  such  facility  that  it  is  really  burdensome 
to  try  and  remember  any  formulas  connecting  these 
properties. 

The  Value  of  Formulas  in  Steam  Engineering. — 
In  certain  theoretical  reasoning,  however,  a  formula 
setting  forth  these  relationships  becomes  often  of  in- 
estimable value  and  indeed  at  times  leads  one  to  at- 
tain data  otherwise  impossible  to  compute.  Such  is 
the  case  of  the  formula  from  which  the  specific  volume 
of  saturated  steam  is  obtained  by  computation  and  set 
forth  in  Chapter  VII.  Here  it  is  found  impossible 
to  obtain  by  experiment  that  which  is  easily  com- 
puted by  application  of  this  formula. 

102 


EMPIRICAL  FORMULAS  103 

We  shall  next  set  forth  some  of  the  comparatively 
simpler  relationships  or  equations  that  have  been  de- 
vised or  annunciated  by  various  authors.  These  will 
serve  to  give  the  student  an  insight  only  into  such 
complicated  formulas  that  arise  in  attempting  a  math- 
ematical expression  for  these  data. 

Unless  one  desires  to  go  deep  into  the  theoretical 
discussions  of  vapors  and  superheated  gases  such  a 
brief  introduction  is  nevertheless  fully  sufficient  for 
the  mastering  of  most  problems  in  steam  engineering 
computation. 

Relation  Between  Temperature  and  Pressure  of 
Saturated  Steam. — It  has  already  been  set  forth  that 
water  boils  or  that  saturated  steam  begins  to  be 
formed  from  water  at  different  temperatures  for  each 
variation  in  pressure.  No  one  as  yet  has  set  forth  a 
simple  rational  formula  connecting  this  relationship. 
In  the  issue  of  Power  of  March  18,  1910,  is  to  be 
found  a  formula  which  is  the  simplest  and  yet  one 
of  the  most  accurate  empirical  relations  yet  estab- 
lished. This  formula  connects  the  temperature  in 
Fahrenheit  degrees  with  the  pressure  in  pounds  per 
sq.  in.  at  which  water  boils,  and  is  as  follows: 

t  =  200p*  —  101 (1) 

For  a  pressure  of  10  Ib.  per  sq.  in.  the  error  is 
but  0.28  per  cent,  while  for  300  Ib.  per  sq.  in.,  it  be- 
comes but  0.32  per  cent.  The  intermediate  values  are 
far  less  in  error,  so  that  this  formula  has,  indeed,  a 
wide  range  of  usefulness. 

The  Total  Heat  of  Saturated  Steam. — Almost  a 
century  ago  Regnault  gave  to  the  world  his  celebrated 
data  on  steam  engineering.  So  accurately  and  so 
carefully  did  he  perform  his  work  that  even  today  his 
experimental  results  are  used  in  steam  engineering 
computation,  although  of  course  corrections  are  ap- 
plied where  certain  constants  involved  in  computation 
are  now  known  to  have  different  values. 

Regnault's  Formula. — Regnault's  formula  for  the 
total  heat  Ht  of  saturated  steam  at  temperature  t  is 
one  of  the  simplest  ever  invented  and  is  as  follows : 

Ht  =  1091.7 +  0.305  (t  — 32)   (2) 


104  FUEL  OIL  AND  STEAM  ENGINEERING 

Let  us  test  this  formula  by  comparing  its  results  with 
those  set  forth  in  the  steam  tables  for  235°  F. 
Regnault's  Formula: 

H235  =  1091.7  +  0.305  (235  —  32)  =1153.6  B.t.u. 

H235=  1158.7  B.t.u. 

1158.7  —  1153.6 

.  • .  Error  = X  100  =  0.44% 

1158.7 

Hence  we  see  that  for  low  temperatures  the  error 
involved  by  using  the  classic  equation  of  Regnault  is 
less  than  one-half  of  one  per  cent. 

Henning's  Formula. — Marks  and  Davis  have  in 
the  rear  of  their  steam  tables  set  forth  a  formula  of 
Henning,  which  though  somewhat  more  complicated 
than  Regnault's  is,  however,  very  accurate.  This 
formula  may  be  expressed  as  follows : 

Ht  =  11 50.3  +  0.3745  (t  — 212)  —0.000550 

(t-212)2  (3) 

Let  us  now  test  the  accuracy  of  this  formula  by  sub- 
stituting the  same  temperature  of  235°  F.  as  used  in 
Regnault's  formula. 
By  Henning's  formula: 

H235  =  1150.3  +  0.3745   (235  —  212)  —0.000550 

(235  — 212)2  =  11 58.64  B.t.u. 
From  steam  tables: 

H235  =  1158.7. 

1158.7  —  il58.64 

.  •  .  Error  =  -     X  100  =  .0052% 

1158.7 

Hence  the  error  involved  in  the  use  of  this  formula 
is  seen  to  be  extremely  slight. 

Latent  Heat  of  Evaporation. — Thiesen,  after  ob- 
serving certain  limits  toward  which  the  latent  heat  of 
evaporation  seemed  to  tend,  suggested  the  following 
formula  for  the  latent  heat  of  evaporation  of  water: 

Lt  =  138.81   (689  — t)  °-315   (4) 

Let  us  compare  this  with  the  steam  table  data  for  a 
temperature  of  235°  F. 
Thiesen's  formula: 

L235  =  138.81  (689  —  235)°-315  =  953.7. 


EMPIRICAL  FORMULAS  105 


Steam  tables : 


L235  =  955.4 

955.4  _  953.7 

.  •  .  Error  =  -  •  X  100  =  0.178% 

955.4 

While  the  error  here  found  is  comparatively  small, 
at  higher  temperatures  this  error  becomes  excessive. 
Hence  we  should  apply  this  formula  with  due  regard  to 
its  limitations. 

A  Second  Formula  for  Heat  of  Evaporation. — Stu- 
dents in  the  classes  of  mechanical  engineering  at  the 
University  of  California  have  established  a  relation- 
ship for  latent  heat  and  temperature  aL  follows : 

L2  =  1209423  —  1289.5  t (5) 

This  formula  is  simple  and  yet  accurate  to  within 
one-third  of  one  per  cent  for  a  wide  range  of  tempera- 
tures of  from  100°  F.  to  350°  F.  and  with  three-fourths 
of  .one  per  cent  for  practically  the  entire  range  involved 
in  steam  engineering  practice.  The  constants  set 
forth  were  obtained  by  the  method  of  Least  Squares. 

Relationship  of  Specific  Volume  for  Superheated 
Steam. — In  the  chapter  on  Heat  and  Elementary  Laws 
of  Thermodynamics,  it  was  shown  that  the  pressure, 
volume,  and  absolute  temperature  of  a  perfect  gas  are 
connected  by  a  very  simple  relationship  as  set  forth  in 
the  composite  formula  given  in  equation  (5).  In- 
deed, it  was  shown  that  while  superheated  steam  is 
not  a  perfect  gas,,  still  for  approximate  results  this 
equation  may  be  used. 

For  accurate  work,  however,  the  equation  of  Linde 
is  found  quite  satisfactory  although  exceedingly  cum- 
bersome in  its  application.  This  equation  connects 
the  pressure  p  in  pounds  per  sq.  in.  and  specific  vol- 
ume v  in  cu.  ft.  per  pound  with  the  absolute  tempera- 
ture T  in  the  following  relationship : 

pv  =  0.5962  T  —  p   (1  + 0.0014  p) 

150300000 
[ -0.0833  ]   (6) 


106  BTJEL  OIL  AND  STEAM  ENGINEERING 

To  illustrate  the  application  of  this  formula,  let  us 
endeavor  to  find  the  specific  volume  of  superheated 
steam  at  526.8°  F.  used  in  a  turbine  test  when  the 
steam  was  under  a  pressure  of  187.2  Ib.  per  sq.  in. 
absolute. 

It  is  seen  that  the  absolute  temperature  of  the 
superheated  steam  was 

T  =  526.8  +  459.6  =  986.4 

and  since  the  absolute  pressure  p  was  187.2  Ib.  per 
sq.  in.,  we  have  by  substitution  in  the  formula 

v  =  3.05 
From  steam  tables : 

v  =  3.05 

Hence  in  this  instance  the  formula  appears  to  be  ab- 
solutely accurate  for  the  range  of  units  involved  in  the 
steam  tables. 

A  Simplified  but  Limited  Formula. — A  convenient 
formula  for  a  pressure  of  175  Ib.  per  sq.  in.,  the  ap- 
proximate pressure  involved  in  steam  turbine  opera- 
tions, has  been  worked  out  by  the  mechanical 
engineering  students  at  the  University  of  California 
for  superheat  between  fifty  and  six  hundred  degrees 
and  is  as  follows : 

v  _  2.67  +  .00377  t,  (7) 

Wherein  ts  is  the  number  of  degrees  superheat.  The 
accuracy  of  this  formula  is  within  one-half  of  one  per 
cent  for  the  range  of  superheat  above  set  forth. 

Other  Relationships  Exist. — By  making  use  of 
certain  theoretic  considerations  in  thermodynamics 
many  other  equations  might  be  written  setting  forth 
still  other  relationships  involved  in  the  determination 
of  steam  constants,  but  sufficient  illustrations  have 
now  been  given  the  reader  for  a  thorough  introduction 
to  such  formulas.  Perhaps  after  all  the  most  impor- 
tant lesson  one  derives  from  their  use  is  that  their 
application  is  often  so  tedious  and  their  range  of  ac- 
curacy often  so  questionable,  that  one  had  better  stay 
on  well  trodden  paths  and  master  to  their  fullest  ex- 
tent the  application  of  the  steam  tables  and  diagrams 
in  the  solution  of  all  steam  engineering  problems. 


CHAPTER  XIII 


THE  FUNDAMENTALS  OF  FURNACE  OPERA- 
TION IN  FUEL  OIL  PRACTICE 

ANY  of  us  are  familiar 
with  the  famous  painting 
that  pictures  James  Watt 
as  a  boy  gazing  in  wide- 
eyed  amazement  at  the 
homely  tea-kettle  spouting 
forth  its  hitherto  unhar- 
nessed power  generating 
vapors.  The  eyes  of  the 
youth  are  illuminated  with 
that  strange  and  wonder- 
ful light  that  set  forth  in 
a  measure  some  of  the 
dreams  of  constructive  im- 
agination which  must 
have  been  filling  his  con- 
sciousness at  that  time. 

The  great  inventor  of 
the  steam  engine  undoubt- 
edly saw  in  the  tea-kettle 
before  him,  not  the  home- 
ly object  of  the  kitchen, 
but  in  its  expanded  form  one  of  the  most  necessary 
mechanisms  for  modern  industrial  development — 
namely,  the  steam  boiler. 

Let  us  then  examine  the  fundamental  operation 
and  construction  of  the  steam  boiler,  and  consider  this 
great  giant  of  modern  industrial  aggrandizement  to 
see  wherein  it  varies  from  its  progenitor — the  homely 
tea-kettle  of  Watt's  boyhood  dream. 

The  Fundamentals  of  the  Tea- Kettle  and  the 
Boiler  are  the  Same. — The  tea-kettle  in  its  construction 


Air  Ducts   for   Furnace 
Floor 


107 


108  FUEL  OIL  AND  STEAM  ENGINEERING 

and  operation  may  be  considered  under  three  sepa- 
rate discussions.  First,  there  must  be  some  means 
of  generating  and  imparting  heat;  secondly,  a  con- 
tainer for  the  water  and  steam  must  be  constructed 
with  physical  characteristics  to  meet  the  stresses  and 
strains  involved ;  and,  thirdly,  the  cycle  of  physical 
operations  through  which  the  water  and  steam  pass 
in  the  generation  of  steam  is  of  vast  importance. 

The  tea-kettle  operation  in  its  simplest  analysis 
consists  of  a  flame  placed  beneath  a  metal  container. 
This  metal  container  absorbs  the  heat  from  the 
flame  and  transmits  it  to  the  water  within  the  con- 
tainer. When  sufficient  heat  has  been  absorbed  by 
the  water  within  the  container  to  raise  its  temperature 
to  the  boiling  point  corresponding  to  the  external  pres- 
sure of  the  atmosphere,  the  tea-kettle  boils  or  in  the 
language  of  the  steam  engineer  the  tea-kettle  generates 
steam. 

In  its  fundamental  makeup,  the  boiler  too,  quite 
closely  follows  this  familiar  and  homely  object — the 
tea-kettle.  For  in  the  modern  boiler  heat  is  first  gen- 
erated in  a  furnace.  This  heat  is  then  imparted  to  a 
metallic  drum  or  tubes  through  which  water  is  passed. 
When  sufficient  heat  is  thus  imparted  to  raise  the  tem- 
perature of  the  water  to  the  boiling  point  for  the 
pressure  involved,  steam  generation  takes  place. 

Inefficiency  of  Tea  Kettle  Operation. — In  modern 
kitchen  economics  but  little  attention  is  paid  to  the 
manner  in  which  the  heat  is  imparted  to  the  tea-kettle. 
Usually  the  stove  lid  is  taken  off  and  the  kettle  placed 
over  the  fire  space  thus  created.  Some  minutes  later, 
the  house-wife,  ignorant  of  the  vast  heat  losses  that 
have  taken  place,  returns  to  draw  off  the  hot  water 
.thus  inefficiently  obtained  as  convenience  may  require. 
As  a  matter  of  fact,  the  slightest  and  most  casual  in- 
vestigation shows  that  in  the  United  States  millions 
of  dollars  are  wasted  every  year  for  lack  of  reasonable 
care  in  the  kettle  operation.  This  loss  is,  nowever, 
so  widely  distributed  over  thousands  of  homes  that 
it  is  not  felt  in  any  concentrated  form. 


FURNACE  OPERATION  109 

Efficiency  in  the  Modern  Steam  Boiler  a  Necessity. 
In  the  case  of  the  modern  central  station,  however, 
efficiency  is  the  cry  of  the  day.  For  with  competition 
on  all  sides  and  regulating  commissions  to  limit  the 


TYPICAL    BOILER    FRONT    IN    FUEL   OIL   PRACTICE 

In  this  illustration  may  be  seen  the  fuel  oil  atomizer  in  the  ash  pit 
entrance,  the  hooded  steam  pipes  for  supplying  steam  used  in  atom- 
ization,  the  fuel  oil  supply  pipes,  the  damper  control,  the  draft 
gage  and  other  accessories  for  fuel  oil  operation. 

prices  charged  for  the  power  supply,  the  utmost  in  eco- 
nomic steam  generation  is  essential. 

Hence,  in  modern  steam  boiler  operation,  espe- 
cially in  its  heat  generating  properties,  a  wide  varia- 
tion from  tea-kettle  operation  is  in  vogue,  not  so 
much  in  fundamental  principles  involved  as  in  effi- 
ciency of  methods  employed  in  the  heat  generating 
mechanisms. 

Efficient  Furnace  Construction  of  Utmost  Im- 
portance. -  -  To  accomplish  this  efficiency  an  enclosed 
compartment  beneath  the  boiler  proper  is  built.  This 
is  known  as  the  furnace.  In  this  iurnace  heat  gener- 
ating substances  such  as  coal,  wood,  and  crude  pe- 
troleum are  burned.  In  the  study  of  chemistry  it  has 
been  found  that  certain  primary  elements,  notably 
carbon,  hydrogen,  and  sulphur,  upon  coming  in  con- 


110  FUEL  OIL  AND  STEAM  ENGINEERING 

tact  with  heated  oxygen  undergo  a  chemical  reaction 
and  in  doing  so  give  out  enormous  quantities  of  heat. 
It  is  the  generation  of  this  heat  and  its  ultimate  ab- 
sorption by  the  water  in  the  boiler  that  makes  the 
modern  steam  engine  and  steam  turbine  the  giants  in 
commercial  enterprise  that  today  they  represent. 

Fuels  Defined. — In  nature,  substances  such  as 
coal,  wood  and  crude  petroleum  are  found  in  vast 
quantities  and  since  these  contain  large  amounts  of 
free  carbon  and  hydrogen,  they  make  excellent  arti- 
cles for  heat  generation  and  are  called  fuels. 

An  Air  Supply  Essential. — It  has  been  mentioned 
that  a  supply  of  oxygen  is  absolutely  necessary  so 
that  a  chemical  reaction  may  take  place  and  thus 
liberate  the  heat  held  in  suspense  in  the  fuel.  The 
air  about  us  is  made  up  of  about  twenty  per  cent 
oxygen  and  eighty  per  cent  nitrogen.  The  nitrogen 
is  an  inert,  valueless  ingredient  that  must  pass  int;o 
the  furnace,  absorb  some  of  its  heat  and  go  out 
through  the  chimney,  thus  conducting  away  into  the 
outer  atmosphere  some  of  the  heat  generated.  The 
oxygen,  however,  upon  coming  in  contact  with  the 
heated  carbon,  hydrogen  and  sulphur  of  the  fuel, 
readily  chemically  reacts  with  them. 

Enormous  quantities  of  heat  are  thus  liberated, 
later  to  be  absorbed  by  the  water  of  the  boiler,  even- 
tually to  produce  the  steam  delivered  for  the  driving 
of  the  steam  engine  or  the  steam  turbine. 

Furnace  Operation. — Since  this  series  of  articles 
is  largely  concerned  with  fuel  oil  practice,  let  us 
briefly  outline  the  furnace  operation  for  such  practice. 
In  a  later  chapter  this  will  be  taken  up  in  more  detail. 

The  Fuel  Oil  Burner  and  Its  Function*— The  fuel 
oil  is  sprayed  into  the  furnace  by  means  of  an  atomizer 
or  burner  which  pulverizes  the  oil  and  delivers  it  in  a 
gaseous  vapor  or  in  small  globules  at  the  hottest  place 
in  the  furnace.  Air  is  admitted  from  below  and  as  soon 
as  the  temperature  is  raised  to  the  ignition  point  chem- 
ical reaction  takes  place  with  the  atomized  fuel  oil, 
and  thus  heat  is  generated.  This  heat  is  absorbed  by 


FURNACE  OPERATION  111 

the  gases  of  the  furnace  and  consequently  their  tem- 
perature is  at  once  raised  often  times  to  2300  deg.  or 
2500  deg.  F.  These  furnace  gases  consist  of  the  inert 
nitrogen  that  partly  constituted  the  entering  air,  the 
carbon  dioxide  or  carbon  monoxide  formed  by  the 
burning  of  the  carbon,  water  vapor  formed  by  the 
burning  of  the  hydrogen,  sulphur  dioxide  formed  by 
the  burning  of  the  sulphur  content,  which  latter  ingre- 
dient is  always  small,  and  a  considerable  quantity  of 
free  oxygen  depending  on  the  amount  of  excess  air 
admitted  to  the  furnace. 

The  Path  of  the  Furnace  Gases. — In  their  ex- 
panded condition,  due  to  the  absorption  of  such  huge 
quantities  of  heat,  the  gases  now  travel  upward.  As 
they  come  in  contact  with  the  boiler  drums  or  tubes 
through  which  water  is  circulating,  the  gases  are,  of 
course,  cooled  and  the  temperature  of  the  water 
raised.  In  this  manner  the  gases,  having  been  chilled 
or  lowered  in  temperature  to  500  deg.  or  600  deg.  F., 
are  finally  passed  up  through  the  chimney,  and  steam 
generation  within  the  boiler  is  accomplished. 

The  Economizer  and  Its  Economic  Value.  -  -  In 
some  boiler  installations  a  series  of  tubes  through 
which  cold  water  is  passing,  is  placed  between  the 
boiler  and  the  chimney.  The  chimney  gases  are  thus 
forced  to  give  up  still  more  of  their  heat.  These  out- 
going chimney  gases  are  consequently  reduced  still 
further  in  temperature. 

Such  a  device,  as  cited  above,  is  known  as  an 
economizer.  This  reduction  in  the  temperature  of 
the  out-going  chimney  gases  reduces  the  draft  of  the 
chimney.  Hence,  the  economizer  is  an  economic  suc- 
cess so  long  as  the  saving  in  feed-water  heating  is 
greater  than  the  interest  on  the  cost  of  the  economizer 
installation  and  other  apparatus  necessary  to  produce 
artificial  draft,  plus  the  cost  of  maintenance  of  this  ad- 
ditional apparatus. 

Quantity  of  Air  Required. — It  has  been  observed 
that  the  entrance  of  air  into  the  furnace  is  absolutely 
•essential  for  furnace  operations.  Too  much  air,  how- 


112  FUEL  OIL  AND  STEAM  ENGINEERING 

ever,  is  detrimental,  for  more  oxygen  may  be  admitted 
than  can  be  economically  used  by  the  fuel.  Hence, 
too  great  an  excess  of  air  simply  means  the  passage 
up  through  the  chimney  of  excess  gases  which  absorb 
heat  only  to  convey  it  out  into  the  atmosphere  with- 
out performing  a  useful  function.  In  successful  boiler 
operation,  therefore,  some  means  must  be  provided, 
first  to  measure  the  draft;  second,  to  test  the  ingre- 
dients of  the  outgoing  gases ;  and  third,  to  regulate  the 
entrance  of  air  into  the  furnace. 

The  Draft  Gage  and  Its  Principle  of  Operation. — 

A  draft  gage  usually  consists  of  a  column  of  water 
placed  in  a  U-tube.  The  pressure  in  the  chimney  is 
less  than  the  atmosphere  without.  Therefore,  if  one 
end  of  this  tube  is  inserted  into  the  chimney  and  the 
other  rests  under  the  atmospheric  pressure  without, 
the  difference  of  water  level  thus  obtained  in  the 
U-tube  indicates  the  draft  in  inches  of  water.  This 
may  be  converted  into  pounds  pressure  (absolute)  per 
square  inch  by  applying  the  formulas  previously  set 
forth  in  the  chapter  on  pressures. 

Apparatus  for  Determining  Ingredients  of  Out- 
going Chimney  Gases. — For  economic  boiler  operation 
the  steam  engineer  should  know  the  exact  composition 
of  the  outgoing  chimney  gases.  Since  this  is  a  matter 
of  vast  importance  a  later  chapter  will  be  given  in 
which  detailed  discussions  of  methods  involved  and 
apparatus  employed  will  be  given.  Suffice  it  to  say 
at  this  point,  however,  that  by  means  of  such  appa- 
ratus the  engineer  may  determine  whether  the  fuel  is 
being  properly  consumed  in  the  furnace  and  whether 
too  little  or  too  much  air  is  being  admitted  into  the 
furnace. 

Draft  Regulating  Devices. — In  fuel  oil  practice  the 
proper  supply  of  air  may  be  determined  to  a  nicety. 
Hence  some  means  must  be  provided  to  regulate  the 
air  supply  with  the  same  precision.  This  is  done  by 
varying  the  amount  of  opening  of  either  the  ash  pit 
doors  or  the  boiler  damper  or  both.  If  the  air  is  reg- 
ulated by  partly  closing  the  ash  pit  doors  and  leaving 


FURNACE  OPERATION  113 

the  damper  wide  open  a  strong  draft  may  occur  inside 
the  boiler  setting  which  tends  to  draw  air  in  through 
the  brick  walls.  As  this  is  a  detriment  it  is  preferable 
to  regulate  the  air  by  means  of  the  damper. 

The  Chimney.  —  After  the  gases  have  passed 
through  and  around  the  various  heat  absorbing  tubes 
and  drums  employed  in  the  modern  steam  boiler  and 
economizer,  they  are  shot  up  into  the  atmosphere 
through  a  long  vertical  passage.  The  structure  hous- 
ing this  passage  is  known  as  a  chimney,  The  height  of 
the  chimney  and  its  area  of  cross-section  through 
which  the  flue  gases  pass  have  an  important  bearing 
on  the  economic  boiler  or  rather  furnace  operation. 

In  a  general  way,  the  reader  now  has  a  grasp  of 
the  fundamentals  involved  in  modern  furnace  opera- 
tion for  the  steam  boiler.  We  shall  next  consider  the 
container  or  shell  for  steam  generation  and  its  acces- 
sories. 


CHAPTER  XIV 

THE  BOILER  SHELL  AND  ITS  ACCESSORIES 
FOR  STEAM  GENERATION  IN  FUEL  OIL 
PRACTICE 


ET  us  now  consider  some 
of  the  fundamental  laws 
involved  in  heat  trans- 
ference, and  then  discuss 
the  container  or  shell  em- 
ployed in  steam  genera- 
tion together  with  the 
accessories  that  must  ac- 
company any  high  pres- 
sure steam  generating 
unit  to  accomplish  safe 
and  efficient  operation. 

Going  back  once  again 
to  the  homely  tea-kettle 
for  a  simple  illustration, 
we  find  that  the  container 
for  the  water  and  steam 
usually  consists  of  a  flat 
bottomed  metallic  vessel 
with  free  opening  to  allow 
the  steam  generated  to 

escape  to  the  atmosphere.  There  is  also  usually  to  be 
found  an  opening  with  a  lid  covering  at  the  top  where 
water  may  be  passed  in  or  the  vessel  cleaned  at  more 
or  less  irregular  periods  of  operation  in  household 
economics. 

In  the  case  of  the  steam  boiler,  however,  vast  im- 
provements in  physical  configuration  and  construction 
become  a  necessity.  Let  us  then  examine  some  of 
these  differences. 


The  C.lean,  Clear  Cut  Appear- 
ance of  the  Oil  Fired 
Boiler   Room 


114 


THE  BOILER  SHELL  115 

The  Laws  of  Heat  Involved  in  Steam  Generation. 

—The  transference  of  heat  is  found  by  experimental 
observation  to  take  place  in  three  separate  and  distinct 
ways — namely,  by  conduction,  by  radiation,  and  by 
convection. 

On  a  wintry  night  if  one  stands  in  front  of  a  blaz- 
ing fireplace  it  is  easy  to  find  illustrations  of  these 
three  methods  of  heat  transference.  Thus  standing, 
one  feels  the  heat  radiating  to  his  face  in  outward  pro- 
jections from  the  fire,  for  if  an  article  such  as  a  solid 
screen,  opaque  to  heat  radiation,  be  placed  between 
the  face  and  the  fire  the  sensation  of  heat  on  the  face 
immediately  disappears.  If  now  from  behind  the 
screen  one  holds  a  metallic  poker  in  the  hot  fire,  it 
will  not  be  long  before  the  poker  even  at  the  point  be- 
hind the  screen  becomes  so  hot  by  conduction  that  it 
cannot  comfortably  be  held  in  the  hand.  And  finally 
should  a  sudden  gust  of  wind  blow  down  the  chimney 
a  hot  gust  of  air  may  be  driven  out  into  the  room  and 
around  the  screen  to  the  observer's  face,  thus  iUustrat- 
ing  the  transference  of  heat  by  convection. 

The  Principle  of  Operation  of  the  Steam  Boiler.— 
Let  us  then  see  how  these  three  methods  of  heat  trans- 
fer are  utilized  in  modern  boiler  operation. 

As  has  been  previously  noted,  the  burning  of  the 
fuel  in  the  furnace  causes  enormous  quantities  of  heat 
to  be  given  out  in  the  furnace  space.  This  heat  is 
immediately  absorbed  by  the  furnace  gases,  thereby 
raising  them  to  a  high  temperature.  By  convection 
currents,  and  also  by  radiation,  this  heat  is  now  trans- 
ferred to  the  outer  surface  of  the  boiler  shell  and 
tubes  containing  the  water  that  it  is  desired  to  con- 
vert into  steam.  The  metallic  shell  and  water  tubes 
having  now  absorbed  the  heat,  convey  it  to  their  inner 
surface  by  conduction  where  it  is  transferred  to  the 
water  in  the  boiler.  This  water,  becoming  heated,  ex- 
pands, and,  due  to  its  lighter  density  thus  created  is 
forced  to  go  to  the  top  of  the  water  surface  to  make 
way  for  cooler,  heavier  water  which  in  turn  absorbs 
heat  and  disappears  to  make  way  for  other  water. 
This  last  activity  is  evidently  again  transference  by 


116  FUEL  OIL  AND  STEAM  ENGINEERING 

convection  currents  and  such  a  movement  of  water 
is  called  circulation.  The  efficient  manner  in  which 
this  circulation  takes  place  has  much  to  do  with  the 
economic  operation  of  the  boiler. 

Mathematical  Equat;on  for  Heat  Transfer. — In 
1909  Dr.  Wilhelm  Nusselt .  of  Germany  devised  a 
formula  whereby  the  factors  involved  in  the  rate  of 
transference  of  heat  are  set  forth  quantitatively.  This 
formula  reduced  to  English  units  by  the  Babcock  and 
Wilcox  Company  in  their  book  on  Steam  is  as  follows : 

xw           (Wcp)-786 
a  =  0.0255 (1) 

(d)--4  (AX) 

Wherein  a  is  the  transfer  rate  in  B.t.u.  per  square 
foot  of  surface  per  degree  difference  in  temperature ; 
W  is  the  weight  of  pounds  of  the  gas  flowing  through 
the  tubes  per  hour;  A  is  the  area  of  the  tube  in  square 
feet,  d  is  the  diameter  of  the  tube  in  feet ;  cp  is  the 
specific  heat  of  the  gas  at  constant  pressure;  x  is  the 
conductivity  of  the  gas  at  the  mean  temperature  and 
pressure  in  B.t.u.  per  hour  per  square  foot  of  surface 
per  degree  Fahrenheit  drop  in  temperature  per  foot; 
and  xw  is  the  conductivity  of  the  steam  at  the  tempera- 
ture of  the  wall  of  the  tube. 

Mathematical  Law  for  Total  Heat  Absorption. — 

The  application  of  this  formula  is  cumbersome  and  in- 
deed upon  careful  analysis  it  is  seen  to  be  largely 
empirical  in  its  nature.  Let  us  then  cast  about  for 
another  equation. 

Stefan's  law  sets  forth  that  the  heat  absorbed 
per  hour  by  radiation  is  proportional  to  the  difference 
of  the  fourth  powers  of  the  absolute  temperature  of  the 
furnace  gases  T  and  the  absolute  temperature  of  the 
tube  surface  t  of  the  boiler.  In  addition  to  this  if 
we  add  the  loss  of  heat  given  up  by  the  outgoing  gases 
due  to  their  cooling  from  the  absolute  temperature  Tt 
to  the  absolute  temperature  T2  on  the  assumption  that 
the  boiler  tubes  have  absorbed  all  this  heat,  we  have 
for  the  total  heat  absorption : 


THE  BOILER  SHELL  117 

T      4  t      4 

E=16QO[(-  -)-( )    1S1  +  WC(T1-T2)...(2) 

1000        1000 

In  which  E  is  the  total  evaporation  of  a  boiler  meas- 
ured in  B.t.u.  per  hour,  S1  is  the  area  of  boiler  surface, 
W  is  the  weight  of  gas  leaving  the  furnace  and  pass- 
ing through  the  setting  per  hour,  and  C  is  the  specific 
heat  of  the  gas. 

Relationship  of  Rate  of  Heat  Transfer. — By  means 
of  the  integral  calculus  it  may  now  be  found  from  the 
above  equation  that  the  rate  of  heat  transfer  R  may  be 
expressed  by  the  equation 

WC               (T,  —  t ) 
R=  -loge-  (3) 

S  (T2-t) 

This  law  shows  an  important  relationship  of  tem- 
peratures whereby  we  may  design  condenser  shells  as 
well  as  boiler  shells  to  accomplish  a  maximum  rate 
of  heat  transfer. 

In  the  Babcock  and  Wilcox  type  of  boiler  the  con- 
stants involved  in  heat  transference  have  been  quite 
accurately  ascertained.  By  substituting  these  con- 
stants the  above  equation  is  found  to  reduce  to  the 
simple  relationship : 

W 

R  =  2.00+.0014-     -   (4) 

A 

Necessity  for  Boiler  Accessories. — Since  the  mod- 
ern boiler  operates  under  pressures  and  temperatures- 
far  in  excess  of  the  tea-kettle  and  since  the  quanti- 
ties of  water  involved  are  far  beyond  hand  operation, 
the  necessity  for  the  creation  of  accessories  to  prop- 
erly care  for  these  increased  responsibilities  early  be- 
came apparent  in  the  evolution  of  steam  engineering. 

Injector  or  Pump  for  Feed  Water  Supply. — In  or- 
der to  supply  the  boiler  with  the  necessary  water  in- 
volved in  steam  generation  the  injector  has  made  its 
appearance  in  some  instances,  while  feed-water  pumps 
are  used  in  other  instances. 


118  FUEL  OIL  AND  STEAM  ENGINEERING 

Since  the  modern  boiler  operates  at  from  100  to 
275  Ib.  pressure  per  sq.  in.,  it  is  evident  that  the  water 
must  be  'forced  into  the  boiler,  for  no  ordinary  water 
supply  is  obtainable  to  meet  such  adverse  pressures. 

The  type  of  pump  most  frequently  met  with  for 


Stop,  Check,  and  Blow-off  Valves 

boiler  feed  purposes  is  the  ordinary  duplex  double  act- 
ing pump  in  which  the  steam  cylinder  is  made  larger 
than  the  water  cylinder  to  enable  the  water  to  be 
forced  into  the  boiler  at  a  pressure  greater  than  that 
of  the  steam  itself.  Pumps  of  this  type  are  very  re- 
liable and  if  chosen  of  sufficient  size  so  they  can  be 
operated  at  slow  speed  give  excellent  satisfaction. 

For  large  power  plants  the  centrifugal  pump  is 
coming  into  favor  owing  to  the  small  space  it  occupies 
and  the  small  attendance  required.  It  is  built  in  four, 
five  or  six  stages,  depending  on  the  water  pressure 
required,  and  may  be  driven  by  either  an  electric  motor 
or  a  small  steam  turbine. 

The  operation  of  the  injector  is  accomplished  by 
drawing  a  certain  amount  of  steam  from  the  boiler  and 
allowing  it  to  attain  an  enormous  velocity.  This 
steam  then  comes  in  contact  with  the  feed  water 
supply  which  at  once  converts  this  impinging  steam 
into  water.  The  immense  impetus  of  the  outflowing 
steam  and  the  conversion  of  the  latent  energy  of  this 
steam  into  kinetic  energy  of  motion  causes  the  feed 
water  to  be  sucked  in  and  driven  against  the  check 
valves  of  the  boiler  with  such  force  as  to  overcome 
the  opposing  pressure  and  allow  such  water  to  enter 
as  may  be  needed. 


THE  BOILER  SHELL  119 

The  injector  is  limited  in  its  field  of  operation  by 
the  fact  that  the  water  must  be  cold  enough  to  con- 
dense the  injected  steam — in  other  words  the  injector 
cannot  pump  hot  water.  As  the  hotter  the  feed  water 
the  more  economical  the  plant  the  injector  is  only  suit- 
able in  plants  where  there  is  no  hot  water  available. 
This  condition  exists  on  the  locomotive  where  the  in- 
jector finds  its  greatest  usefulness. 

Check  and  Non-Return  Valves. — In  order  that  no 
water  should  flow  back  out  through  the  entrance  valve, 
some  means  must  be  provided.  Many 
types  of  valve  are  used  in  practice  to 
perform  this  function.  An  illustration 
of  a  typical  type  of  check  valve  is 
shown  in  the  picture  exhibited  here- 
with. 

The  Steam  Gage  and  the  Water 
Gage. — In  the  operation  of  the  tea- 
Pet  c^ks  for  kettle  the  escaping  of  the  steam  into 
water  Level  the  atmosphere  readily  prevents  the 
possibility  of  explosion,  and  the  ever  watchful  eye 
of  the  attendant  is  utilized  to  see  to  it  that  the 
water  supply  is  sufficient  for  safe  operation.  The  use 
of  high  pressures  and  inclosed  boiler  shells  makes 
it  imperative  in  steam  engineering  to  have  some 
means  of  ascertaining  the  pressure  under  which  the 
boiler  is  operating  and  to  determine  the  height  of 
the  water  in  .the  boiler  shell.  The 
steam  gage  meets  the  former  require- 
ment. This  type  of  instrument  was 
described  in  the  chapter  on  pressures. 

To  ascertain  the  water  level  in  the 
boiler  shell,  the  installation  of  water 
columns  enclosed  in  glass  tubes  makes 
visible  the  height  of  the  water  in  the 
A  Safet    Gage    boiler.     The  water  column  is  located 
so  that  its  center  is  at  about  the  proper 
height  of  water  in  the  boiler.     The  upper  end  of  the 
column  is  connected  to  the  steam  space  of  the  boiler 
and   the  lower  end  to  the  water  space,  so  that  the 


120  FUEL  OIL  AND  STEAM  ENGINEERING 

water  in  the  column  always  rises  to  the  same  height 

as  the  water  in  the  boiler.     The  bottom  of  the  glass 

must  be  a  little  higher  than  the  lowest  level  at  which 

it  is  safe  to  carry  the  water  to  prevent  damage  by 

overheating  the  sheets  or  tubes,  and  the  top  of  the 

glass  must  be  a  little  lower  than  the  level  at  which 

water  would  begin  to  be  lifted  and  carried  out  with 

the    &team.     Pet-cocks     are    provided    so    that    the 

|B    water  column  may  be  cleaned  of  sedi- 

\    ment   at   frequent   intervals   to   insure 

^^^  its  safe  and  accurate  operation.     Since 

^HvHMH    the    ascertaining    of   the    exact    water 

^^r  \    height   in    the   boiler   is    of   such   vast 

•  importance,      three      additional      pet- 

\\  jJll    cocks  called   Gage   Cocks   are   usually 

^h|H^fll     installed  near  the  water  glass.    One  of 

these  is  located  above  the  proper  water 

level,   the  second   at  about  the  water 

[   level,  and  the  third  below  it.     Hence, 

upon  trial  if  the  boiler  is  properly  op- 
siphon   for   Keep-  .  ,        ,,  .        ,,.          .      , 
ing  steam  Gage  erasing,  the  first  should  emit  colorless 

Dry  dry  saturated  steam,  the  second  water 

vapor  and  the  third  hot  water. 
Manholes. — To  clean  and  examine  the  boiler  in- 
terior some  means  must  be  provided  by  which  access 
may  be  had  to  its  interior.  On  all  modern  types  of 
boilers  will  be  found  man-holes  and  hand-holes  where- 
by this  access  may  be  obtained  when  occasion  arises. 
Provision  for  Expansiorai. — The  excessive  temper- 
atures under  which  a  boiler  operates  and  the  sudden 
change  from  one  temperature  to  another  make  it  abso- 
lutely imperative  that  some  means  be  provided  to 
take  care  of  uneven  expansion  in  its  parts.  Most  boil- 
ers on  the  market  do  not  for  this  reason  allow  the 
boiler  shell  to  rest  upon  the  furnace  structure,  but 
on  the  other  hand  the  boiler  is  suspended  from  above 
and  all  suspended  parts  .are  allowed  to  swing  free 
with  ample  clearance  between  them  and  the  brick- 
work. The  care  with  which  uneven  expansion  and 
its  disastrous  results  are  provided  for  makes  much 
for  efficient  boiler  design. 


THE  BOILER  SHELL 


121 


The  Mud  Drum. — Since  all  water  contains  a  cer- 
tain amount  of  impurities,  some  space  must  be  set 
aside  for  the  collection  and  segregation  of  ithese  im- 
purities. Such  a  compartment  is  known  as  the  mud 
drum.  This  is  cleansed  at  definite  periods  by  blowing 
down  the  boiler,  that  is  by  opening  the  blow-off  valve 
at  the  bottom  of  the  mud  drum  and  allowing  some  of 
the  water  to  escape  from  the  boiler  into  the  atmos- 
phere. 

Safety  Valve. — All  boilers  are  definitely  stand- 
ardized so  that  steam  generation  must  not  exceed  a 
certain  pressure  development.  To 
prevent  this  excessive  generation  of 
pressure  a  safety  valve  is  always  in- 
stalled. These  are  in  general  of  two 
types,  the  one  having  its  outlet  to 
the  outside  air  controlled  by  a  spring 
set  for  the  pressure  desired,  the 
other  controlled  by  a  weight  and 
lever  arm  set  for  the  blow-off  pres- 
sure desired.  Since  the  total  pres- 
sure required  to  open  the  valve 
equals  its  area  in  square  inches  times 
the  pressure  in  pounds  per  square 
inch  the  compression  in  the  spring  or  the  weight  on 
the  lever  may  be  determined  in  advance  for  any  de- 
sired pressure  in  the  boiler. 

Having  now  a  general  ground  work  of  boiler 
shell  characteristics  in  their  relation  to  heat  transfer, 
and  bearing  in  mind  the  accessories  that  must  accom- 
pany the  modern  boiler,  we  shall  next  consider  the 
commercial  type  of  boiler  and  its  classification. 


Pop   Safety 
Valve 


CHAPTER  XV 


A    Battery    of    Fifteen 

oil-fired,   requiring  but   Two 
Men   for  Their   Operation 


BOILER  CLASSIFICATION  IN  FUEL  OIL 
PRACTICE 

N  the  generation  of  steam 
by  the  tea-kettle  the  cycle 
of  operations  through 
which  the  water  and  steam 
pass  is  quite  simple.  The 
heat  applied  at  the  bottom 
of  the  tea-kettle  is  ab- 
sorbed by  the  water  along 
its  surface  exposed  to  the 
heat  application.  As  this 
heat  is  absorbed  the  water 
Boilers  is  raised  in  temperature 
and  due  to  its  immediate 
expansion  becomes  lighter 
than  the  water  above  it  and  {consequently  passes 
to  the  top  to  allow  cooler  water  to  descend,  which  in 
turn  becomes  heated  and  passes  to  the  top  to  make 
way  for  still  other  water  to  become  heated.  This  cycle 
of  operations  continues  and  finally  evaporation  takes 
place.  The  steam  thus  generated  passes  to  the  atmos- 
phere without. 

In  the  modern  high  pressure  steam  boiler  the  op- 
eration is  somewhat  more  complicated.  The  water 
circulation  proceeds  on  the  same  general  principle  but 
since  steam  generation  is  the  important  function  and 
not  merely  the  supplying  of  hot  water  as  in  the  tea- 
kettle, some  space  must  be  provided  wherein  to  store 
the  steam  that  is  generated.  This  is  usually  accom- 
plished in  the  space  above  the  water  level  in  the  main 
boiler  shell  or  drum.  If  superheated  steam  is  to  be  pro- 
duced, the  saturated  steam  is  conveyed  from  this  space 

122 


BOILER  CLASSIFICATION  123 

into  tubes  known  as  a  superheater.  These  tubes  are 
exposed  to  the  hot  furnace  gases  and  the  steam  pass- 
ing through  them  readily  absorbs  heat,  thus  super- 
heating the  saturated  steam  to  any  temperature  de- 
termined upon. 

The  Boiler  Drum  and  Tubes. — It  has  been  men- 
tioned that  the  tea-kettle  is  a  most  inefficient  boiler  and 
so  it  is.  While  mechanical  stresses  and  strains  in- 
volved necessitate  the  employment  of  cylindrical  shells 
for  boilers,  still  the  boiler  itself  resembled  in  the  early 
days  of  the  steam  engine  but  slight  variations  from 
the  tea-kettle. 

It  soon  became  apparent,  however,  that  the  actual 
surface  exposed  to  the  heated  gases  of  the  furnace  has 
much  to  do  with  efficient  steam  generation.  Hence 
while  the  first  type  of  boiler  was  made  in  a  solid  shell, 
variations  from  this  standard  soon  made  their  appear- 
ance. Let  us  now  examine  some  of  these  types. 

Internally  and  Externally  Fired  Boilers. — In  the 

earlier  type  of  boiler  the  fire  was  kindled  beneath  the 
solid  cylindrical  boiler  shell.  Such  a  type  became 
known  as  an  externally  fired  boiler.  Later  the  boiler 
compartment  was  hollowed  out  and  the  fire  kindled  in- 
side this  hollow  space,  thus  introducing  the  internally 
fired  type.  The  locomotive  boiler  is  today  an  illus- 
tration of  this  type  of  boiler. 

The  Return  Tubular  Boiler. — Another  type  soon 
developed  wherein  the  fire  was  kindled  beneath  and 
the  flue  gases  returned  to  the  front  part  of  the  boiler 
through  a  series  of  flutings  or  tubes  passing  through 
the  main  part  of  the  boiler  shell.  Such  a  boiler  became 
known  as  a  return  flue  boiler  or  return  tubular  boiler 
depending  upon  whether  or  not  the  tubes  or  flutings 
exceeded  six  inches  in  diameter — the  flue  being  the 
larger  diameter  and  the  tube  the  smaller. 

The  Fire  Tube  and  the  Water  Tube  Boiler. — A 

great  many  types  of  boilers  finally  made  their  appear- 
ance on  the  market  in  some  of  which  the  fire  passed 
through  the  tubes  which  were  surrounded  by  water  in 
the  boiler  shell,  and  in  other  instances  the  water  passed 


124 


FUEL  OIL  AND  STEAM  ENGINEERING 


THE   B.  &  W.    MARINE  TYPE   OF   BOILER— FRONT    VIEW 

Water  tube  boilers  for  marine  service  are  built  as  modifications  of 
both  the  B.  &  W.  and  the  Heine  type,  the  tubes  being  shorter  and 
smaller  in  diameter  than  is  the  case  in  stationary  boilers.  These 
boilers  are  encased  in  steel,  lined  with  light  insulating  material  in- 
side, instead  of  being  set  in  brick.  They  are  constructed  of  the 
highest  grade  of  forged  steel.  Marine  boilers  frequently  carry 
pressures  as  high  as  300  Ib.  per  sq.  in. 

through  the  tubes  around  the  external  surface  of  which 
the  heated  gases  were  made  to  pass.  The  former  be- 
came known  as  fire  tube  while  the  latter  were  called 
water  tube  boilers.  It  is  generally  conceded  that  where 
rapid  steaming  is  required  the  latter  type  is  far  prefer- 
able. 

It  is  now  universally  the  custom  to  use  water  tube 
boilers  in  large  stationary  power  plants.  The  prin- 
cipal reasons  are  the  following: 

1.  Small  floor  space  required. 

2.  Greater   safety   at  high   pressures   due  to  the   small 
diameter  of  the  drums  and  tubes. 


BOILER  CLASSIFICATION 


125 


THE   B.  &  W.    MARINE  TYPE   OF    BOILER— REAR      VIEW 

3.  Greater  flexibility  so  that  expansion  strains  are  not 
injurious. 

4.  Rapid  steaming  and  sudden  change  of  load  more 
easily  accommodated. 

Tubular  boilers  still  have  their  field  in  small  one 
man  plants,  where  owing  to  the  large  quantity  of  water 
contained  in  the  shell  they  maintain  a  uniform  pres- 
sure with  but  little  attention. 

Tubular  boilers  of  the  Scotch  marine  type  are  still 
extensively  employed  in  marine  work  where  owing  to 
the  steadiness  of  the  load  they  have  met  with  great 
success. 

Vertical  and  Horizontal  Types. — Still  other  clas- 
sifications are  made  based  upon  whether  the  tubes  and 
boiler  shell  be  in  a  horizontal  or  vertical  position,  the 
former  being  called,  as  one  would  presume,  the  hori- 
zontal and  the  latter  the  vertical  type  of  boiler.  As 
time  went  on  still  other  boilers  appeared  which  could 


126  FUEL  OIL  AND  STEAM  ENGINEERING 

neither  be  called  horizontal  nor  vertical  but  an  inter- 
mediate classification  became  necessary. 

Let  us  now  examine  two  types  of  boiler  used  in  the 
modern  central  station  in  order  the  more  clearly  to 
grasp  the  fundamentals  of  boiler  design  and  principles 
of  operation. 

Illustrations  of  Principles  of  Construction  and  Op- 
eration.— Before  proceeding  to  the  brief  description  6f 
these  two  types  of  boiler,  the  reader  must  bear  in  mind 
that  these  particular  two  are  picked  as  best  setting 
forth  principles  of  construction  and  operation,  and  not 
necessarily  as  a  preference  for  commercial  installation. 
Many  types  of  boiler  are  today  upon  the  market  and 
in  their  separate  and  distinctive  features  such  possess 
characteristics  that  must  be  carefully  considered  in 
making  a  commercial  choice.  With  this  understanding 
let  us  then  proceed  to  examine  these  two  boiler  types 
of  commercial  practice. 

The  Babcock  and  Wilcox  Boiler. — By  a  close  ex- 
amination of  the  illustration  shown  on  page  10,  the 
Babcock  and  Wilcox  boiler  is  seen  to  be  composed  of 
one  or  more  horizontal  shells  or  drums  from  which  are 
suspended  a  series  of  inclined  tubes. 

In  this  type  of  boiler  installation  the  oil  burner  is 
located  in  the  rear  of  the  furnace  and  the  fuel  oil  is 
shot  forward  toward  the  front ;  thus  this  type  is  known 
as  the  "Back-shot"  type  of  installation.  The  heated 
gases  then  pass  upward  and  around  the  tubes  through 
what  is  known  as  the  first  pass.  At  the  top  of  this 
pass  the  heated  gases  envelop  the  lower  half  of  the 
boiler  shell  and  are  then  diverted  downward  through 
and  around  the  superheater  tubes  shown  immediately 
below  the  drum  until  the  journey  through  the  second 
pass  is  completed.  At  the  rear  of  the  furnace  wall 
they  are  once  again  diverted  upward  through  the  third 
pass  and  then  after  contact  with  the  boiler  shell,  they 
are  conveyed  out  through  the  breeching  up  the  stack 
or  chimney.  In  this  manner  the  heated  gases  are 
brought  into  intimate  contact  with  the  water  tubes  and 
efficient  steam  generation  accomplished. 


BOILER  CLASSIFICATION  127 

Water  Circulation. — The  water  for  steam  gener- 
ating purposes  is  introduced  through  the  front  drum- 
head of  the  boiler.  It  then  passes  to  the  rear  of  the 
drum,  downward  through  the  rear  circulating  tubes  to 
the  sections.  Then  it  courses  upward  through  the 
tubes  of  the  sections  to  the  front  headers  and  through 
these  headers  and  front  circulating  tubes  again  to  the 
drum  where  such  water  as  has  not  been  formed  into 
steam  retraces  its  course.  The  steam  formed  in  the 
passage  through  the  tubes  is  liberated  as  the  water 
reaches  the  front  of  the  drum.  The  steam  so  formed  is 
stored  in  th£  steam  space  above  the  water  line. 

The  Parker  Boiler. — Another  type  of  boiler  which 
is  exceedingly  interesting,  as  its  operating  principles 
are  almost  diametrically  opposite  to  the  foregoing  is 
that  of  the  Parker  boiler. 

As  seen  from  the  illustration  on  page  18,  the  fuel 
oil  is  shot  from  the  front  of  the  furnace  to  the  back. 
The  heated  gases  in  their  journey  toward  the  rear  come 
in  contact  with  the  lower  set  of  tubes  and  at  the  rear 
they  pass  up  through  the  superheater.  They  are  then 
deflected  back  horizontally  toward  the  front,  passing 
parallel  along  the  water  tubes.  At  the  front  they  return 
again  to  the  rear  along  the  third  set  of  tubes  and  also 
along  the  lower  half  of  the  boiler  drum  above. 

Water  Circulation. — Water  enters  the  upper  set  of 
horizontal  tubes  from  the  front  without  passing  first 
into  the  boiler  drum  above.  At  the  rear  it  is  conveyed 
upward  into  the  drum  which  has  a  longitudinal  dia- 
phragm separating  the  steam  section  above  from  the 
water  section  beneath.  This  water  having  emptied 
upon  the  diaphragm  in  the  upper  compartment  flows 
down  along  the  diaphragm  to  the  front.  At  this  point 
it  is  dropped  down  into  the  next  section  of  tubes  to  be 
again  discharged  upward  into  the  upper  rear  section  to 
flow  again  down  along  the  diaphragm  to  the  front  and 
again  to  be  lowered  into  the  lowest  section  of  hori- 
zontal tubes  to  return  into  the  diaphragm  section  above 
as  saturated  steam. 


128 


FUEL  OIL  AND  STEAM  ENGINEERING 


It  is  seen  by  comparing  those  two  types  of  steam 
generation  that  contrary  and  opposite  theories  are 
used.  The  fiirst  fires  the  oil  flame  from  the  back 
toward  the  front,  while  the  latter  applies  the  opposite 
process.  The  first  admits  the  water  into  the  drum  and 


A  Milwaukee  High  Pressure  Horizontal  Tubular  Boiler 
with  Full  Front  and  Suspension  Setting 

then  produces  a  water  circulation  from  the  lower  sec- 
tions upward;  the  latter  takes  the  water  first  through 
the  top  sections  and  winds  up  at  the  lower.  The  first 
sets  forth  the  theory  of  right  angle  impingement  of 
heated  gases  against  the  water  tube  surface  while  the 
latter  takes  the  paralleling  flow  theory.  The  remark- 
able thing  about  the  whole  comparison  is  that  both 
have  produced  wonderfully  efficient  steam  generating 
achievements  in  carefully  conducted  fuel  oil  tests  on 
the  Pacific  Coast. 

The  Stirling  Type. — The  Stirling  boiler  consists 
of  three  steam  drums  connected  to  one  mud  drum  by 
means  of  bent  tubes.  The  bending  of  the  tubes  does 
away  with  the  necessity  of  using  headers  and  further- 
more provides  for  expansion  of  the  tubes  due  to 
change  in  temperature.  As  a  result  this  boiler  is  not 
only  simple  in  design  but  very  flexible  and  capable 
of  withstanding  a  good  deal  of  abuse.  The  baffles  are 


BOILER  CLASSIFICATION  129 

arranged  in  such  a  manner  that  the  gases  of  com- 
bustion travel  up  the  front  bank  of  tubes,  down  the 
middle  bank  and  up  the  rear  bank.  This  boiler  may 
be  fired  by  either  the  front  shot  or  the  back  shot 
oil  burner.  With  the  front  shot  burner  the  flame  is 
forced  right  among  the  front  bank  of  tubes  which  are, 
therefore,  effective  as  heating  surfaces.  The  back  shot 
burner  has  the  advantage  of  shooting  the  gases  for- 
ward to  a  large  combustion  chamber  so  that  more 
perfect  combustion  can  be  obtained,  although  at  the 
expense  of  making  the  heating  surface  of  the  front 
bank  of  tubes  less  effective  owing  to  the  fact  that 
the  gases  do  not  come  in  such  intimate  contact  with 
these  tubes. 

Other  boilers  of  the  general  Stirling  type  are  the 
Badenhausen,  the  Rust  boiler  and  the  Erie  City  ver- 
tical boiler. 

The  Heine  Type. — The  Heine  boiler  is  a  horizontal 
water  tube  boiler  similar  to  the  B.  &  W.  boiler  ex- 
cept that  instead  of  having  separate  headers  the  tubes 
are  all  expanded  into  a  single  water  leg  at  the  rear 
and  another  at  the  front.  These  water  legs  have  large 
flat  surfaces  which  have  to  be  strengthened  by  stay 
bolts.  Owing  to  the  fact  that  all  of  the  tubes  are 
connected  to  the  same  water  legs,  this  boiler  is  not 
as  flexible  as  the  other  two  types  described  above. 
The  Heine  boiler  is  usually  provided  with  horizontal 
baffles  so  that  the  gases  of  combustion  pass  first  to 
the  rear  of  the  boiler  and  then  forward  among  the 
tubes  and  then  back  again.  With  this  arrangement 
of  baffling  the  front  shot  oil  burner  introduced  through 
the  front  wall  is  very  successful.  Other  boilers  of  the 
Heine  type  are  the  Keeler  and  Edgemoor  boilers. 

Marine  Boilers. — For  mercantile  marine  service 
the  standard  boiler  for  many  years  has  been  the  Scotch 
marine  boiler  which  is  a  fire  tube  boiler  consisting 
of  a  large  shell  within  which  are  placed  corrugated 
furnaces,  a  combustion  chamber  at  the  rear  and  tubes 
running  forward  from  the  combustion  chamber  to  the 
front  of  the  boiler,  whence  the  gases  pass  through 


130  FUEL  OIL  AND  STEAM  ENGINEERING 

the  uptakes  to  the  smokestacks.  Owing  to  the  large 
size  of  the  shell,  Scotch  boilers  are  made  of  excess- 
ively thick  steel  and  consequently  are  entirely  lacking 
in  flexibility.  They  are,  therefore,  liable  to  give  trou- 
ble due  to  expansion  strains  from  change  in  tempera- 
ture and  are  successful  only  where  the  load  is  abso- 
lutely steady  as  it  is  on  ordinary  merchant  ships. 

In  the  navy  water  tube  boilers  are  used  exclu- 
sively and  these  are  coming  into  use  more  or  less 
in  the  mercantile  marine  as  well. 

Water  tube  marine  boilers  are  built  as  modifica- 
tions of  both  the  B.  &  W.  and  the  Heine  types,  the 
tubes  being  shorter  and  smaller  in  diameter  than  is  the 
case  in  stationary  boilers  and  the  boilers  being  en- 
cased in  steel,  lined  with  light  insulating  material  in- 
side, instead  of  being  set  in  brick. 

For  torpedo  boat  destroyers  and  other  small  high 
speed  craft,  boilers  of  the  Thornycroft  type  are  used, 
which  consist  of  a  large  number  of -very  small  diam- 
eter tubes  expanded  into  upper  and  lower  drums. some- 
what similar  in  general  type  to  the  Stirling  stationary 
boiler.  TheSe  boilers  are  extremely  light  and  are 
rapid  steamer^  which  are  necessary  characteristics  of 
bbifers  for  high  speed  boats. 


CHAPTER  XVI 

FUEL   OIL   AND    SPECIFICATIONS    FOR 
PURCHASE 

ETROLEUM  has  been 
known  in  the  United 
States  from  prehistoric 
times.  It  is  certain  that 
the  mound  builders  had 
wells  from  which  petro- 
leum was  obtained.  These 
are  still  in  existence  along 
with  the  most  modern  of 
our  own  times. 

Petroleum  was  usedy  as 
a  medicine  by  many  tribes 
of  Indians.  It  was  sup- 
posed to  have  many  mag- 
ical as  well  as  medicinal 
properties.  Its  inflammable 
nature  seems  also  to  have 

The  Saybolt  Electrical  Equip-   been  known. 

ment  for  Flash  and  AT  '..  .'  •> 

Fire  Tests  No  use  was  discovered 

for  petroleum  other  than1 

as  a  medicine  until  in  1852;  when  a  chemist,  by  the 
name  of  KiefJ  bethought  himself  of  distilling  it  and 
extracting  'froni  it  the  more  volatile  portions!  The 
American  people  took  readily  to  the  use  of  these  oils 
as  illuminating  agents  from  the  fact  that  for  some  time 
previously  the  mineral  oils,  extracted  from  lignites 
and  anthracites,  according  to  the  process  of  Sellegries, 
the  Swiss  chemist,  were  in  current  use. 

Enormous  Consumption  of  Fuel  Oil  in  the  Indus- 
tries.— The  use  of  crude  petroleum  as  a  fuel  .for  steam 
generation  and  power  production  has  now  an  .estab- 
lished position  in  all  parts  of  the  industrial  world. 


131 


132-  FUEL  OIL  AND  STEAM  ENGINEERING 

Especially  is  this  true  on  the  Pacific  Coast  and  in  the 
southwestern  section  of  the  United  States  where  the 
enormous  yield  of  this  product  in  Oklahoma,  Texas 
and  California  now  constitutes  an  ever-increasing-  fac- 
tor in  the  total  production  of  the  world.  Indeed,  Cali- 
fornia alone  with  her  yield  of  over  one  hundred  million 
barrels  in  1917  produced  over  25  per  cent  of  the  world's 
output. 

At  ite  first  incipiency  it  was  thought  that  the 
probable  production  of  crude  petroleum  would  be 
limited  to  but  a  few  years.  Due  to  this  factor  many 
power  plants  on  the  Pacific  Coast  were  constructed  so 
that  an  easy  change  over  to  operation  by  coal  could 
be  made  should  this  time  ever  arrive.  It  is  now  recog- 
nized by  many  that  the  probable  yield  of  oil  will  last 
as  long  as  the  coal  fields  of  the  world.  Hence  this 
uncertainty  is  largely  dispelled  in  the  industrial  pro- 
duction of  power. 

Advantages  of  Crude  Petroleum  as  a  Fuel. — Oil 
has  many  distinct  advantages  over  coal.  Due  to  the 
simple  mechanisms  that  are  involved  the  cost  for 
handling  fuel  oil  is  far  less  than  for  coal.  By  the 
elimination  of  stokers  an  important  labor  item  is  found 
unnecessary.  Again  for  equal  heat  value  oil  occupies 
much  less  space  than  coal.  Hence  for  ocean-going 
vessels  it  is  especially  applicable.  Combustion  too  is 
more  perfect,  so  that  the  quantity  of  excess  air  re- 
quired is  reduced  to  a  minimum.  The  furnace  tem- 
perature may  be  kept  practically  constant  as  the  fur- 
nace doors  need  not  be  opened  for  cleaning  or  work- 
ing the  fires.  Smoke  may  to  a  large  measure  be  elim- 
inated with  the  consequent  cleanliness  of  heating  sur- 
faces. Again,  the  intensity  of  the  fire  is  subject  to 
delicate  regulation  and  sudden  load  fluctuations  are 
easily  handled.  Oil  does  not  disintegrate  or  lose  its 
calorific  value  when  stored.  In  the  boiler  room  the 
cleanliness  and  freedom  from  dust  and  ashes  results 
in  a  saving  in  wear  and  tear  in  machinery.  Hence  it 
is  clearly  evident  that  the  efficiency  and  the  steaming 
capacity  of  a  boiler,  oil-fired,  is  increased  in  a  marked 
manner. 


FUEL  OIL  SPECIFICATIONS  133 

The  disadvantages  of  fuel  oil  are  of  comparatively 
small  moment.  For  this  reason  wherever  oil  can  be 
obtained  at  a  reasonable  figure  as  compared  to  the 
prevailing  market  price  of  coal  it  has  attained  a 
marked  popularity  in  steam  generation  and  in  the 
industries. 

Let  us  then  look  into  some  of  the  physical  prop- 
erties of  this  new  and  important  source  of  heat  gen- 
eration. 

Liquid  Fuels  Classified. — Petroleum  is  practically 
the  only  liquid  fuel  sufficiently  abundant  and  cheap 
to  be  used  for  the  generation  of  steam.  There  are 
three  kinds  of  petroleum  in  use,  namely,  those  yielding 
on  distillation  paraffin,  asphalt  and  olefine.  To  the 
first  group  belong  the  oils  of  the  Appalachian  Range 
and  the  Middle  West  of  the  United  States.  These  are 
a  dark  brown  in  color  with  a  greenish  tinge.  Upon 
their  distillation  such  a  variety  of  valuable  light  oils 
are  obtained  that  their  use  as  a  fuel  is  prohibitive 
because  of  price.  To  the  second  group  belong  the  oils 
found  in  Texas  and  California.  These  vary  in  color 
from  reddish  brown  to  a  jet  black.  Since  they  are 
used  extensively  as  a  fuel  in  the  United  States,  our 
discussion  in  this  chapter  shall  largely  be  concerned 
with  this  class  of  oils.  The  third  group  comprises  the 
oils  from  Russia,  which  like  the  second  group  are  used 
largely  for  fuel  purposes. 

Physical  and  Chemical  Properties  of  Oil. — Mineral 
oils  as  found  in  nature,  are  a  mixture  in  indefinite 
proportions  of  several  combinations^  hydrogen  and 
carbon  designated  as  hydrocarbons.  Oxygen  and  sul- 
phur are  found  in  very  small  amounts.  Nitrogen  is 
found  in  a  smaller  proportion  than  the  latter. 

On  account  of  the  complexity  of  their  composition, 
mineral  oils  differ  considerably  both  physically  and 
chemically. 

Odor  and  Color. — Oil  is  generally  found  in  a  very 
fluid  condition  in  North  and  South  America,  while  in 
Russia  and  East  India  it  is  found  in  a  very  dense  and 
syrupy  condition.  They  all  possess  a  characteristic 


134  FUEL  OIL  AND  STEAM  ENGINEERING 

odor  while  their  color  varies  from  amber  or  greenish 
yellow  to  dark  brown.   By  reflection  they  are  all  greenish. 

Effect  of  Heat.— Heat  will  separate  the  different 
hydrocarbons  successively  according  to  their  volatility 
and  cause  them  to  dissociate  at  higher  temperatures. 
Low  temperatures  will  solidify  these  products,  the 
highest  freezing  at  a  lower  temperature. 

Density  of  Various  Oils. — The  density  varies  from 
0.765  to  0.970  compared  with  water  at  4  degrees  C.,  as 
found  in  nature  (crude).  Distillates  will  be  much 
lighter. 

Densities    of    Oils 

Orig-in  of  Crude  Specific  Gravity 

Persia    . 0.777 

East  Indies 0.821 

Kyouk-Phyon  (Burma)    0.818 

California 0.960 

,                         Pennsylvania 0.850 

South    America 0.852 

Russia  ..i 0.836 

India   .,...- 0.955 

Terra-di-Lavors   (Italy) 0.970 

Physical  Properties  of  California  Oils. — We  shall 
now  consider  as  a  typical  example  a  sample  of  Cali- 
fornia crude  petroleum  taken  from  an  average  of  forty 
samples  drawn  from  the  Kern  River  oil  field  by  repre- 
sentatives of  the  U.  S.  Bureau  of  Mines. 

The  specific  gravity  or  density  of  fuel  oil  is  an  im- 
portant factor  to  be  known  and  is  the  ratio  of  the 
weight  of  an  oil  sample  as  compared  with  the  weight 
of  an  equal  volume  of  water.  The  average  oil  sample 
is  found  to  have  a  specific-gravity  of  .9645,  which  on 
the  Baume  scale  at  60°  F.  is  15.16°.  Hence,  the  aver- 
age gallon  of  fuel  oil  weighs  8.03  Ibs. 

The  determination  of  the  gravity  of  fuel  oil  and 
the  relat:onship  of  specific  gravity  with  gravities  ex- 
pressed on  the  Baume  scale  are  of  such  importance 
that  a  subsequent  chapter  has  been  set  aside  for  de- 
tailed discussion  and  analysis. 

The  Calorific  Value  of  Fuel  Oil.— In  steam  boiler 
economy  the  heat  prod ucingj  value  of  the  fuel  per 
pound  consumed  in  the  furnace  is  of  utmost  impor- 


FUEL  OIL  SPECIFICATIONS  135 

tance.  The  average  sample  of  Kern  River  oil  gen- 
erates or  gives  out  10,307  calories  per  gram,  which 
^transferred  to  steam  engineering  units  is  found  to  be 
;  18,553  B.t.u.  per  pound  or  148,980  B.t.u.  per  gallon 
of  oil. 

Oil,  like    water,    requires    the    actual    absorption 
of    an    enormous    quantity  of    heat  in  its  conversion 


LABORATORY    EQUIPMENT    FOR    FUEL    OIL    TESTING 

In  the  gathering  of  fuel  oil  data  for  boiler  tests  the  three  things 
to  be  ascertained  accurately  are  the  specific  gravity,  the  moisture 
content,  and  the  calorific  value  of  the  oil  sample.  The  principal 
pieces  of  apparatus  necessary  are  the  Westphal  Balance,  the  chem- 
ist's scales,  a  Parr  calorimeter,  and  a  still  with  their  accessories  as 
shown.  In  the  text  of  this  article  these  physical  characteristics  of 
fuel  oil  are  set  forth.  In  later  discussions  the  laboratory  procedure 
in  order  to  ascertain  each  of  these  points  will  be  discussed  in  sep- 
arate chapters. 


into  the  gaseous  state.  Indeed  the  latent  heat  of 
evaporation  for  fuel  oil  is  approximately 966  B.t.u.  per 
pound  under  atmospheric  pressure,  as  compared  with 
9/jQ.4  for  the  latent  heat  of  evaporation  of  water  as 
set;  forth  in  previous  discussions.  Hence,  the  actual 
heat  given  out  by  the  average  sample  above  referred 
to  is  approximately  19,519  B.t.u.  per  pound,  but  since 


136     .         FUEL  OIL  AND  STEAM  ENGINEERING 

we  must  gasify  the  oil  to  make  use  of  its  heat  gen- 
erating characteristics  in  the  furnace  the  net  value  of 
18,553  is  solely  of  commercial  importance. 

The  determination  of  the  calorific  value  of  fuel  oil 
and  the  many  computations  involved  are  of  such  vast 
importance  that  several  chapters  have  been  set  aside 
for  future  discussions  of  these  various  factors. 

The  Flash  Test  and  the  Burning  Point  of  Oil.— 
The  flash  test  of  an  oil  is  the  temperature  at  which  it 
gives  off  inflammable  vapors.  For  the  purpose  of 
safety  in  handling,  fuel  oils  should  not  give  off  inflam- 
mable vapors  below  150°  F.  The  flash  point  of  an  oil 
is  determined  by  heating  the  oil  in  a  vessel  adjacent 
to  which  is  a  small  flame.  When  the  oil  has  been 
heated  to  a  point  where  vapor  rises  and  ignites  from 
the  flame,  this  temperature  is  called  the  flash  point. 
The  flash  point  of  the  average  California  oil  is  108°  C. 
or  226.4°  F. 

The  burning  point  of  oil  is  the  temperature  at 
which  its  ingredients  will  permanently  ignite.  This  is 
determined  by  continuing  the  heating  of  the  oil  after 
the  flash  point  has  been  ascertained  until  the  "flash" 
becomes  permanent,  that  is,  until  the  oil  ignites  and 
continues  to  burn  quietly.  For  the  average  Kern 
River  oil  sample  the  burning  point  is  found  by  the 
open  cup  test  to  be  130°  C.  or  266°  F. 

Viscosity. — Some  oils  are  more  fluid  or  mobile 
than  others.  All  are  familiar  with  the  difference  be- 
tween "cold  molasses"  and  "  hot  molasses."  And  so 
in  oil  flow  we  have  a  similar  phenomenon.  This  ten- 
dency for  the  particles  of  oil  to  cohere  to  one  another 
is  known  as  viscosity.  Viscosity  is  determined  by 
measuring  the  time  it  takes  oil  to  flow  through  a 
standard  sized  tube  under  standard  conditions.  On 
the  so-called  Engle's  scale  the  average  viscosity  of 
Kern  River  oil  at  20°  C.  is  found  to  be  915.6.  The  vis- 
cosity is  very  materially  lessened  as  the  temperature 
is  increased.  Hence  at  once  is  seen  the  advantages 
of  oil  heating  both  for  efficiency  in  transmission 
through  long  pipe  lines,  and  for  feeding  the  oil  to  the 


FUEL  OIL  SPECIFICATIONS  137 

burners.  In  power  plants  the  oil  is  heated  to  a  tem- 
perature of  160°  F.  before  reaching  the  burners. 

Moisture.  —  All  oils  have  a  certain  quantity  of 
moisture  present  either  in  a  free  state  or  in  the  form 
of  an  emulsion,  and  its  presence  is  always  a  hindrance 
to  the  full  development  of  the  heat  producing  qualities 
of  the  oil,  Since  this  is  a  matter  of  great  importance, 
the  methods  used  in  the  quantitative  determination  of 
moisture  present  in  fuel  oil  will  be  set  forth  in  a  sub- 
sequent chapter.  The  average  Kern  River  sample 
contains  about  .5  per  cent  moisture.  Hence  the  actual 
fuel  oil  ingredient  is  99.5  per  cent. 

Sulphur,  Gas  and  Other  Ingredients. — All  oils 
have  a  certain  quantity  of  sulphur  present.  This  sul- 
phur has  a  heat  producing  quality,  yet  its  deleterious 
effect  in  producing  obnoxious  gases  and  the  corroding 
effect  it  has  on  the  boiler  tubes  and  other  metallic 
parts  makes  a  certain  excess  of  sulphur  most  undesir- 
able in  the  use  of  fuel  oil.  The  average  Kern  River 
oil  sample  contains  .83  per  cent  sulphur.  There  is  no 
gasoline  ingredient  found  in  this  oil  sample.  On  the 
other  hand,  refined  lamp  oil  appears  to  the  extent  of 
6.6  per  cent  and  refined  lubricants  to  the  extent  of 
39.2  per  cent.  The  refining  losses  are  5.9  per  cent  and 
distilling  losses,  .5  per  cent.  The  commercial  asphaltum 
present  is  47.3  per  cent,  thus  indicating  why  California 
oils  are  known  as  possessing  an  asphaltum  base. 

Specifications  for  the  Purchase  of  Oil. — In   the 

above  discussion  of  the  physical  properties  of  fuel  oil 
it  is  seen  that  the  flashpoint,  burning  point,  viscosity, 
heating  value,  moisture  content,  sulphur  content,  and 
other  characteristics  are  fundamentally  concerned  in 
the  commercial  evaluation  of  crude  petroleum.  The 
United  States  government  is  a  great  consumer  of  fuel 
oil  and  below  are  given  eleven  important  items  estab- 
lished by  the  U.  S.  Bureau  of  Mines  to  aid  the  gov- 
ernment in  properly  specifying  its  requirements  for 
oil  purchases.  The  points  set  forth  are  also  of  funda- 
mental importance  for  the  economic  use  of  fuel  oil  in 


138  FUEL  OIL  AND  STEAM  ENGINEERING 

all  steam  boiler  practice  and  the  reader  should  carefully 
bear  them  in  mind. 

Specifications  for  Fuel  Oil 

(1)  In  determining  the  award  of  a  contract,  con- 
sideration  will   be   given   to   the   quality   of  the   fuel 
offered  by  the  bidders,  as  well  as  the  price,  and  should 
it  appear  to  be  to  the  best  interest  of  the  government 
to  award  a  contract  at  a  higher  price  than  that  named 
in  the  lowest  bid  or  bids  received,  the  contract  will 
be  so  awarded. 

(2)  Fuel  oil  should  be  either  a  natural  homoge- 
neous oil  or  a  homogeneous  residue  from  a  natural  oil ; 
if  the  latter,  all  constituents  having  a  low  flash  point 
should  have  been  removed  by  distillation ;  it  should 
not  be  composed  of  a  light  oil  and  a  heavy  residue 
mixed  in  such  proportions  as  to  give  the  density  de- 
sired. 

(3)  It  should  not  have  been  distilled  at  a  tem- 
perature high  enough  to  burn  it,  nor  at  a  temperature 
so  high  that  flecks  of  carbonaceous  matter  began  to 
separate. 

(4)  It  should  not  flash  below  60°  C.  (140°  F.)  in  a 
closed  Abel-Pensky  or  Pensky-Martens  tester. 

(5)  Its   specific   gravity   should  range   from  0.85 
to  0.96  at  15°  C.  (59°  F.)  ;  the  oil  should  be  rejected 
if  its  specific  gravity  is  above  0.97  at  that  temperature. 

(6)  It  should  be  mobile,  free  from  solid  or  semi- 
solid  bodies,  and  should  flow  readily,  at  ordinary  at- 
mospheric  temperature   and   under  a   head   of   1   foot 
of  oil,  through  a  4-inch  pipe  10  ft.  in  length. 

(7)  It  should  not  congeal  nor  become  too  sluggish 
to  flow  at  0°  C.  (32°  F.) 

(8) 'It  should  have  a  calorific  value  of  not  less 
than  10,000  calories  per  gram  (18,000  British  thermal 
units  per  pound);  10,250  calories  to  be  the  standard. 
A  bonus  is  to  be  paid  or  a  penalty  deducted  according 
as  the  fuel  oil  delivered  is  above  or  below  this  standard. 


FUEL  OIL  SPECIFICATIONS  139 

(9)  It  should  be  rejected  if  it  contains  more  than 
2  per  cent  water. 

(10)  It  should  be  rejected  if  it  contains  more  than 
1  per  cent  sulphur. 

(11)  It  should  not  contain  more  than  a  trace  of 
sand,  clay,  or  dirt. 


CHAPTER  XVII 

BOILER   ROOM    INSTRUCTIONS    FOR    FUEL 
OIL  BURNING 

Many  fatal  accidents  both  to  life  and  property 
have  happened  due  to  foolhardy  methods  in  design 
and  operation  of  the  steam  boiler.  This  early  became  • 
so  apparent  that  rigid  governmental  inspection  of 
boiler  operation  was  insisted  upon.  To  aid  in  sys- 
tematic inspection  the  Department  of  Commerce  and 
Labor  at  Washington  has  issued  general  rules  and 
regulations  for  such  supervision  under  Form  801  en- 
titled Steamboat  Inspection  Service.  Many  insurance 
companies  have,  too,  put  into  force  rigid  rules  of  in- 
spection to  safeguard  their  interests  in  assuming 
risks.  The  most  complete  publication  on  the  sub- 
ject, however,  is  to  be  found  in  the  recently  published 
report  of  the  Boiler  Code  Committee  of  the  American 
Society  of  Mechanical  Engineers,  entitled :  "Rules 
for  the  Construction  of  Stationary  Boilers  and  for  Al- 
lowable Working  Pressure."  These  rules  have  been 
adopted  by  law  in  a  number  of  States,  including  Cali- 
fornia where  they  have  been  incorporated  in  the  Safety 
Orders  of  the  State  Accident  Commission. 

In  the  discussion  taken  up  in  this  chapter  only 
fundamentals  will  be  considered.  The  thorough  mas- 
tering of  these  fundamentals  will,  however,  enable 
the  reader  to  understandingly  read  the  deeper  discus- 
sions alluded  to  above. 

The  Inspection  Tests  Involved. — The  testing  of 
the  water  and  steam  gages,  the  checking  of  fittings 
and  appliances,  and  the  trying  out  of  the  safety  valves 
and  other  accessories  constitute,  of  course,  important 
details  of  boiler  inspection.  The  most  important  fea- 
ture, however,  is  to  ascertain  by  computation  the 
maximum  allowable  working  pressure  that  may  be 

140 


BOILER  ROOM  INSTRUCTIONS 


141 


safely  put  upon  the  boiler.  After  this  maximum  al- 
lowable pressure  is  ascertained  the  boiler  is  subjected 
to  a  hydrostatic  pressure  test  by  filling  the  boiler 


AN    INSPECTOR'S  TESTING   AND   PROVING   OUTFIT 

Here  is  a  typical  outfit  for  boiler  and  power  plant  inspectors.  It 
consists  of  a  standard  test  gage,  a  screw  test  pump,  a  gage  hand 
puller,  a  hand  set  and  other  useful  conveniences. 

completely  with  water  and  then  pumping  enough  ad- 
ditional water  into  it  to  raise  the  pressure  to  the  de- 
sired point.  This  apparatus  is  held  under  proper  con- 
trol and  the  total  pressure  put  upon  the  boiler  is  one 
and  one-half  times  the  maximum  allowable  working 
pressure. 

Thus   if  the   maximum   allowable   working  pres- 
sure on  a  boiler  is  160  Ibs.  per  square  inch  above  the 


142  FUEL  OIL  AND  STEAM  ENGINEERING 


he  test  pressure'  t0  b#  \  applied-  should  he 
j24Q  Ibs,.  pef  square  inch. 

Many  carefully  compiled  instructions  have  from 
time  to  time  been  issued  by  various  boiler  makers, 
inspectors,  and  others  interested  in  economic  and  safe 
operation.  The  instructions  compiled  by  J.  B.  Warner, 
chief  inspector  of  the  San  Francisco  department  of 
the  Hartford  Steam  Boiler  Inspection  and  Insurance 
Company  are  especially  good,  and  largely  the  ideas 
appearing  in  the  following  lines  come  from  this 
source  : 

Preliminary  Precautions.  —  Whenever  going  on  duty 
in  the  boiler  room,  find  out,  first  of  all,  where  the 
water  level  is  in  the  boilers.  Never  lower  nor  re- 
plenish the  fires  until  this  is  done.  Make  sure  that 
the  gage  glass  and  gage  cocks,  and  all  the  connections 
thereto,  are  free  and  in  good  working  order.  Do  not 
rely  upon  the  glass  altogether,  but  use  the  gage  cocks 
also,  and  try  them  all,  several  times  a  day. 

Before  starting  up  the  fires,  open  each  door  about 
the  setting  and  look  carefully  for  leaks.  If  leaks  are 
discovered,  either  then  or  at  any  other  time,  they 
should  be  located  and  repaired  ;  but  cool  the  boiler  off 
first.  If  leaking  occurs  at  the  fore  and  aft  joints,  the 
inspecting  company  should  be  notified  at  once.  This 
is  important,  whether  the  attendant  considers  the 
leakage  serious  or  not;  and  it  is  especially  important 
when  the  boiler  has  a  single  bottom  sheet,  or  is  of 
the  two-sheet  type. 

When  a  boiler  has  been  emptied  of  water,  do  not 
fill  it  again  until  it  has  become  cold. 

In  preparing  to  get  up  steam  after  the  boiler  has 
been  out  of  service,  be  sure  that  the  manhole  and  hand- 
hole  joints  are  tight.  Do  not  use  gaskets  that  are  thin 
and  hard. 

Vent  the  boiler  in  some  way,  first,  to  permit  the 

escape  of  air.    Then  fill  the  boiler  to  the  proper  level, 

open   the   dampers,   and   start   the   fires.      Start   them 

early  so  as  to  have  the  pressure  up  at  the  required 

'hour,  without  forcing. 


BOILER  ROOM  INSTRUCTIONS 


143 


Ventilate  the  setting  thoroughly  before  lighting 
the  fire.  Never  turn  on  the  fuel  supply  when  start- 
ing up  without  first  placing  in  the  furnace  a  lighted 
torch  or  a  piece  of  burning  waste  to  ignite  the  fuel 
instantly. 

Connecting  up  Boiler  Units.-— In  firing  up  a  boiler 
that  is  to  be  connected  with  others  that  are  already 
in  service,  keep  its  stop-valve  closed  until  the  pressure 


A   PORTABLE    BOILER  TEST   PUMP 

After  the  maximum  allowable  working  steam  pressure  for  the 
boiler  has  been  computed,  the  boiler  is  then  submitted  to  a  hydro- 
static test  of  one  and  one-half  times  this  allowable  pressure.  The 
above  apparatus  is  especially  adapted  for  those  having  frequent 
occasion  to  make  hydrostatic  tests  of  boilers. 

within  the  boiler  has  become  exactly  equal  to  that 
in  the  steam  main.  Then  open  the  stop  valve  a  bare 
crack,  and  slowly  increase  the  opening  until  the  valve 
is  wide  open.  The  complete  operation  should  occupy 
two  minutes  or  more.  Close  the  valve  at  once  if  there 
is  the  slightest  evidence  of  any  unusual  jar  or  dis- 
turbance about  the  boiler.  See  that  the  steam  main 
to  which  the  boiler  is  to  be  connected  is  thoroughly, 
•drained  before  the  valve  is  opened. 

Low  Water  Encountered. — In  case  of  low  water; 
immediately  shut  off  the  oil  supply  at  the  burners; 
Do  not  turn  on  the  feed  under  any  circumstances,  and 
do;  not  open  the  safety-valve  nor  tamper  with  it ..  in 


1^4  FUEL  OIL  AND  STEAM  ENGINEERING 

any  way.     Let  the  steam  outlets  remain  as  they  are. 
Get  your  boiler  cool  before  you  do  anything  else. 

Avoid  Making  Repairs  Under  Pressure. — No  re- 
pairs of  any  kind  should  be  made,  either  to  boilers  or 
to  piping,  while  the  part  upon  which  the  work  is  to  be 
done  is  under  pressure.  This  applies  to  calking,  to 
tightening  up  bolts  under  pressure,  and  to  repairs  of 
any  kind  whatsoever. 

The  safety-valve  must  not  be  set  at  a  pressure 
higher  than  that  permitted  by  the  insurance  com- 
pany's policy.  Try  all  safety-valves  cautiously,  every 
day.  If  the  actual  blowing  pressure,  as  shown  by  the 
gage,  exceeds  the  pressure  at  which  the  valve  is  sup- 
posed to  blow,  inform  the  office  immediately,  so  that 
prompt  notice  may  be  sent  to  the  company.  The 
safety-valve  pipe  should  never  have  a  stop-valve 
upon  it. 

Removal  of  Sediment. — To  remove  sediment  from 
the  bottom  of  the  boiler,  open  the  blowoff  valve  in 
the  morning,  or  before  the  circulation  has  started  up. 
The  valve  should  be  opened  wide  for  a  few  moments, 
but  it  should  be  opened  and  closed  slowly,  so  as  to 
avoid  shocks  from  water-hammer  action.  When  sur- 
face blowoffs  are  used,  they  should  be  opened  fre- 
quently, for  a  few  minutes  at  a  time. 

In  case  of  foaming,  check  the  draft  and  shut  off 
the  burners.  Shut  the  stop-valve  long  enough  to  find 
the  true  level  of  the  water.  If  this  is  sufficiently  high, 
blow  down  some  of  the  water  in  the  boiler,  and  feed 
in  some  fresh.  Repeat  this  several  times  if  necessary. 
If  the  foaming  does  not  stop,  cool  the  boiler  off,  empty 
it,  and  find  out  the  cause  of  the  trouble. 

Keep  Out  Cylinder  Oil. — Cylinder  oil  must  be  kept 
out  of  the  boilers,  because  it  is  likely  to  cause  over- 
heating of  the  plates.  Oily  deposits  may  be  removed, 
in  large  measure,  by  scraping  and  scrubbing,  although 
more  efficient  methods  of  treatment  may  be  required 
in  bad  cases.  If  kerosene  is  used  in  a  boiler,  keep  all 
open  lights  away  from  the  manholes  and  handholes, 
both  when  applying  the  kerosene,  and  upon  opening 


BOILER  ROOM  INSTRUCTIONS  145 

the  boiler  up  afterwards ;  and  ventilate  the  inside  of 
the  boiler  thoroughly,  after  oil  has  been  used  in  it. 

Fusible  plugs  should  be  filled  with  pure  tin. 
They  should  be  renewed  or  refilled  as  often  as  may  be 
necessary  to  keep  them  in  good  condition. 

Cooling  and  Cleaning  the  Boiler.-^In  cooling  a 
boiler  before  emptying  it,  first  let  the  fire  die  out,  and 
then  close  all  doors  and  leave  the  damper  open  until 
the  pressure  falls  to  the  point  at  which  it  is  desired 
to  blow.  Clean  the  furnace  and  let  the  brickwork  cool 
for  at  least  two  hours  before  opening  the  blowoff 
valve.  If  it  is  desired  (to  cool  the  boiler  further,  after 
it  has  been  emptied  open  the  manhole  and  leave  every- 
thing else  as  in  full  actual  service  -  -  the  fire  doors, 
front  connection  doors,  and  cleaning  doors  being 
closed,  and  the  damper  and  ash-pit  doors  open. 

First  cool  the  boiler  as  explained  in  the  last  para- 
graph. Never  blow  out  under  a  pressure  exceeding 
ten  or  (at  most)  fifteen  pounds  by  the  gage. 

The  engineer  must  find  out  for  himself  how  often 
h;s  boilers  need  to  be  opened  and  cleaned.  In  many 
plants  it  is  necessary  to  clean  every  week,  while  in 
some  favored  few  it  is  sufficient  to  clean  every  three 
months.  When  using  kerosene  or  large  amounts  of 
scale  solvent,  or  when  (as  in  the  spring-time)  the 
water  becomes  unusually  soft,  the  boilers  must  be 
opened  oftener  than  usual.  In  washing  out  a  boiler, 
wash  the  tubes  from  above,  as  well  as  from  below. 

Never  touch  any  valve  whatsoever,  in  any  part 
of  the  room,  while  a  man  is  inside  of  a  boiler,  nor 
even  after  he  has  come  out  again,  until  he  has  report- 
ed that  his  work  is  finished  and  that  he  will  not  enter 
the  boiler  again.  It  is  well  to  lock  the  stop-valve  and 
blowoff  valve  upon  every  boiler  in  which  a  man  is 
working,  while  other  boilers  are  under  steam.  Pad- 
locks and  chains  may  be  used  for  this  purpose. 

In  water-tube  boilers  the  covers  opposite  the 
three  rows  of  tubes  nearest  the  fire  should  be  taken  off 
once  a  month,  and  the  tubes  thoroughly  scraped  and 
washed  out;  and  all  the  tubes  should  be  thoroughly 
scraped  and  washed  out  at  least  once  in  four  months. 


146  FUEL  OIL  AND  STEAM  ENGINEERING 

This  is  for  water  of  average  quality.     If  the  water  is 
bad,  clean  the 'tubes  oftener. 

When  mechanical  hammers  or  cleaners  are  em- 
ployed for  removing  scale  from  tubes,  the  pressure 
used  to  operate  them  should  be  as  low  as  will  suffice 
to  do  the  work.  Do  not  allow  the  cleaner  to  operate 
for  more  than  a  few  seconds  upon  any  one  spot,  and 
see  that  it  goes  entirely  through  the  tube.  Avoid  high 
temperatures  in  the  steam  or  water  used  to  operate 
the  cleaner. 

Putting  Boiler  Out  of  Service.  -  -  In  putting  a 
boiler  out  of  service,  it  should  be  cooled,  emptied,  and 
thoroughly  cleaned,  both  inside  and  outside.  The  set- 
ting should  likewise  be  cleaned  in  all  its  parts.  Leave 
the  handhole  covers  and  manhole  plates  off.  After 
washing  the  interior  of  the  boiler,  let  it  drain  well. 
Then  see  that  no  moisture  can  collect  anywhere  about 
the  boiler,  nor  drip  upon  it  either  'internally  or  exter- 
nally. Empty  the  siphon  below  the  steam  gage  if  the 
boiler  room  is  likely  to  be  cold,  or  take  the  gage  off 
and  store  it  safely  away. 

Do  not  allow  moisture  to  come  in  contact  with 
the  outside  of  the  boiler  at  any  time,  either  from  leaky 
joints  or  otherwise.  Keep  the  mud  drums  and  nipples, 
and  the  rear  ends  of  horizontal  and  inclined  tubes  in 
water-tube  boilers,  free  from  sooty  matter.  If  internal 
corrosion  is  discovered,  notify  your  employers  at  once. 

Examine  your  boilers  carefully  in  all  their  parts, 
whenever  they  are  laid  off,  and  keep  them  as  clean 
as  possible,  both  inside  and  outside.  See  that  all 
necessary  repairs  are  made  promptly  and  thoroughly. 
Keep  the  wrater  glass  and  pressure  gage  clean  and 
well  lighted.  If  any  contingency  arises  that  you  do 
not  understand,  report  the  matter  to  your  employers 
at  once;  and  if  you  think  it  possible  that  ;serious 
trouble  may  be  impending  at  any  time,  shut  down  the 
boiler  .immediately. 

Inform  yourself  respecting  any  local  laws  or  or- 
dinances relating  to  the  duties  of  engineers  and  fire- 
men, or  to  the  plant  in  which -you  work.  If  there  be 
any  such;  attend  to  them  faitHfully. 


-CHAPTER  XVIII 

HOW  TO  COMPUTE  STRENGTH  OF  BOILER 
SHELLS  IN  FUEL  OIL  PRACTICE 

In  order  to  ascertain  by  computation  the  maximum 
allowable  pressure  we  must  first  compute  the  bursting 
strength  of  the  solid  boiler  shell,  then  find  the  weak- 
est part  of  this  shell,  which,  of  course,  will  give  us 


rt-r.t 


k _._.       t&'-        -- 

STANDARD   FORM   OF  TEST  SPECIMEN 

In  order  to  thoroughly  test  out  plate  material  for  boilers,  a  form  of 
standard  specimen  has  been  established  by  the  Boiler  Code  Com- 
mittee of  the  American  Society  of  Mechanical  Engineers.  The 
above  illustration  shows  the  standard  form  for  the  tension,  cold- 
bend,  and  quench-bend  test  to  be  made  from  each  boiler  plate  as 
rolled. 

the  point  where  the  shell  would  really  give  way.  We 
next  compute  the  steam  gage  pressure  that  would 
cause  the  boiler  to  rupture  at  this  weakest  point.  This 
is  known  as  the  bursting  pressure.  It  is  important  to 
note  here  the  difference  between  the  bursting  pressure 
of  the  boiler  and  the  bursting  strength  of  the  boiler  shell. 
The  former  indicates  the  reading  of  the  steam  gage  at 
which  the  bursting  will  take  place  while  the  latter  indi- 
cates the  unit  internal  pressure  in  the  boiler  material 
when  rupture  occurs. 

As  a  working  gage  pressure  for  boiler  operation 
a  factor  of  safety  of  5  is  often  used — that  is,  a  gage 
pressure  1/5  that  of  the  bursting  pressure  is  consid- 
ered as  the  largest  gage  pressure  that  may  be  safely 
put  upon  the  boiler.  It  should  be  noted  that  when 
'considering  the  safety  of  a  boiler  we  always  deal  with 

147 


148  FUEL  OIL  AND  STEAM  ENGINEERING 

gage  pressure  and  not  absolute  pressure.  The  burst^ 
ing  pressure  of  a  boiler  is  the  difference  between  the 
pressure  inside  the  boiler  and  the  pressure  outside, 
when  rupture  would  occur,  and  as  the  latter  is  always 
the  pressure  of  the  atmosphere  the  bursting  pressure 
must  be  the  amount  the  inside  pressure  would  be 
above  the  atmospheric  pressure,  which  is  the  same 
thing  as  gage  pressure. 

In  order  to  ascertain  the  breaking  strength  of  boil- 
er material,  a  sample  known  as  a  standard  form  is  put* 
to  test.  Experimentally  it  has  been  found  that  whether 
a  piece  of  material  is  subjected  to  rupture  by  tension, 
compression,  or  shear,  the  unit  force  required  to  rup- 
ture a  square  inch  section,  is  equal  to  the  total  force 
observed  in  rupturing  the  specimen  in  each  particular 
case  divided  by  the  cross-sectional  area.  This  funda- 
mental law  enters  largely  in  computation  of  boiler 
strength.  Let  us  then  proceed  to  this  analysis. 

The  Strength  of  the  Solid  Plate.— In  the  study  of 
gases  and  vapors  it  has  been  experimentally  estab- 
lished that  the  pressures  exerted  by  such  substances 
are  felt  equally  in  all  directions  at  any  given  point  un- 
der consideration.  Let  us  then  consider  the  most  dis- 
astrous direction  for  pressure  action.  This  evidently 
would  be  in  such  a  direction  as  would  tend  to  tear  the 
boiler  shell  apart.  If  the  length  of  shell  considered  be 
of  length  p  equal  to  the  distance  from  center  to  center 
of  the  riveted  section  or  what  is  known  as  the  pitch 
of  the  rivets,  we  have  for  a  boiler  of  thickness  t  a 
resisting  area  of  pt  square  inches.  If  the  solid  shell 
will  not  burst  until  each  square  inch  of  area  has  upon 
it  a  unit  force  of  St  pounds,  the  total  resistive  force, 
according  to  the  experimental  law  stated  in  the  pre- 
vious paragraph  is  evidently  pt  St.  Hence  if  A  is  the 
strength  of  solid  plate,  we  have 

A  =  tpSt (1) 

Rule  I.  Multiply  the  thickness  of  the  plate  by  the 
pitch  of  the  rivets  and  by  the  tensile  strength  of  the 


STRENGTH  OF  BOILER  SHELLS 


149 


plate.     The  result  is  equal  to  the  strength  of  solid 
plate. 


A    DIAGRAMATIC    REPRESENTATION    OF    INTERNAL 
BOILER   PRESSURE 

Since  the  pressure  of  a  vapor  is  exerted  equally  in  all  directions  we 
should  consider  that  direction  which  would  produce  the  most  active 
results  in  tearing  apart  a  boiler  when  deducing  expressions  for  the 
safe  working  pressure.  In  order  to  ascertain  the  total  pressure 
tending  to  burst  the  riveted  section  shown  in  the  middle  figure 
above,  the  pressure  should  be  taken  with  the  direction  as  shown 
by  the  arrows  in  this  figure. 

As  an  illustration,  let  us  compute  the  strength  of 
the  solid  plate  for  a  boiler  whose  thickness  of  shell 
is  ]/$  in.,  whose  spacing*  of  rivets  is  1^  in.,  and  whose 
tensile  strength,  stamped  upon  the  boiler  plate  is  found 
to  read  55,000  Ib.  per  sq.  in. 

Applying  Rule  I,  we  have  that  the  strength  of 
solid  plate  is 

A  =  tpSt  =  0.25  X  1.625  X  55,000  =  22,343  Ib. 

The  Strength  of  the  Net  Section.— As  in  the  case 
of  the  weakest  link  determining  the  strength  of  the 
chain,  so  the  strength  of  the  boiler  shell  is  determined 
by  its  weakest  section.  This  will  evidently  be  at 
the  point  where  the  shell  has  been  perforated  for  the 
insertion  of  rivets.  The  actual  area  that  will  resist 
rupture  is  now  no  longer  pt  but  since  it  has  been 
weakened  'by  an  area  dt  wherein  d  represents  the 
diameter  of  the  rivet  hole,  B,  the  net  resistive  force 
now  becomes 

B  =  (pt  —  dt)  St  =  (P  —  d)  tSt (2) 

Rule  II  (a).  From  the  pitch  of  the  rivet  subtract 
the  diameter  of  the  rivet  hole,  then  multiply  by  the 
thickness  of  the  plate  and  again  by  the  tensile  strength 
of  the  plate.  This  result  is  equal  to  the  strength  of 


150  FUEL  OIL  AND  STEAM  ENGINEERING 

the  plate  between  rivet  holes — in  other  words  to  the 
strength  of  the  net  section. 

Taking  as  an  illustration  the  same  boiler  men- 
tioned in  Rule  I,  we  have,  if  the  diameter  of  trie  rivet 
hole  is  11/16  in.,  that  the  strength  of  the  plate  B  be- 
tween rivet  holes  is 

B  =  (p  —  d)  tSt  =  (1.625  —  0.6875)    0.25  X  55,000 
=  12,890  Ib. 

Resistance  to  Shear. — A  boiler  may  not  only  fail 
by  bursting  apart  the  actual  shell  material  but  the 
rivet  itself  may  give  way.  Under  pressure  the  riveted 
boiler  seam  may  pull  apart  and  cut  or  shear  off  the 
rivet  similar  to  the  action  that  would  take  place  by 
using  a  huge  pair  of  shears.  The  area  of  cross-section 
of  the  rivet  is  evidently  the  only  opposition  that  such 
an  action  would  receive  over  the  distance  between  one 
set  of  rivets  in  case  of  a  single  row  of  rivets,  or  if  there 
be  n  rows  of  rivets,  the  area  resisting  shear  is  n  times 
that  for  a  single  row.  Hence,  the  force  that  would 
oppose  rupture  due  to  shear  is  evidently  n  (.7854d2) 
SB,  where  Ss  is  the  pounds  pressure  exerted  over  each 
square  inch  of  cross-section  under  shear.  From  re- 
sults shown  by  tests,  average  iron  rivets  will  shear  at 
38,000  Ib.  per  sq.  in.  in  single  shear  and  76,000  Ibs. 
in  double  shear;  steel  rivets  at  44,000  Ibs.  in  single 
shear  and  88,000  Ibs.  in  double  shear.  Hence  we 
have  that  the  resistance  to  shear  C  for  a  riveted  sec- 
tion is 

C  ==  .7854d2nSs  (3) 

Rule  II  (b).  Multiply  the  area  of  the  rivet 
(.7854d2)  by  the  shearing  resistance  as  follows  If 
iron  rivets  in  single  shear,  allow  38,000  pounds  per 
sq.  in.  of  section,  or  if  of  steel  allow  44,000  pounds 
per  sq.  in.  If  the  resistance  is  in  double  shear  add 
100  per  cent  to  the  above.  The  result  is  the  bursting 
pressure  for  shear. 

Continuing  the  example  above  cited,  we  have  that 
the  shearing  strength  C  of  one  rivet  in  single  shear  is 


STRENGTH  OF  BOILER  SHELLS  151 

C  =  n  X  .7854d2Ss  =  1  X  .7854  X  -68752  X  44,000 
[   '=16,332  Ib. 

Resistance  to  Compression. — Again  the  rivet  may 
be  forced  to  give  way  by  having  its  longitudinal  sec- 
tion (dt)  actually  crushed  if  the  total  crushing  force 
of  the  steam  pressure  exceed  dtSc,  where  Sc  is  the 
crushing  pressure  in  Ib.  per  sq.  in.  over  each  unit 
area  of  the  rivet.  Hence  the  resistance  to  compression 
D  is 

D  =  dtSc . . .  (4) 

Rule  II  (c).  Multiply  the  diameter  of  the  rivet  by 
the  thickness  of  the  boiler  plate  and  then  multiply  by 
the  unit  bursting  stress  for  compression  for  the  rivet 
which  is  taken  at  95,000  Ib.  per  sq.  in.  The  result  is 
equal  to  the  strength  of  the  rivet  section  for  compres- 
sion. 

The  resistance  to  compression  D  for  the  example 
above  cited  is  then 

D  =  dtSc  =  0.6875  X  0.25  X  95,000  =  16,328  Ib. 

The  Efficiency  of  the  Riveted  Section. — We  now 

see  that  the  riveted  section  weakens  the  solid  plate 
in  three  ways.  In  the  first  place,  the  boiler  may  give 
way  more  easily  because  a  section  equal  to  the  rivet 
hole  has  been  cut  from  the  solid  plate.  In  the  second 
place,  the  rivet  may  be  actually  sheared  in  two,  and 


©©©©©©©©© 


•Shearing 
1  Point  , 


A    SINGLE    RIVETED    LAP    JOINT    FOR    BOILER    PLATES 

By  taking  into  consideration  the  stresses  involved  in  a  sectional 
distance  equal  to  the  pitch  of  the  rivets,  P,  as  shown,  we  are  en- 
abled , to  deduce, the  safe  working  gage  pressure  for  boiler  opera- 
tion. 

in  the  third  place,  it  may  be  crushed  longitudinally. 
The  next  thing  to  do  then  is  to  determine  the  ratib 
that'  each  one  of '  these  factors  bbafs'  to  the  strength 


152  FUEL  OIL  AND  STEAM  ENGINEERING 

of  the  solid  plate  and  adopt  the  weakest  or  smallest 
ratio  as  the  possible  point  where  rupture  will  take 
place.  Compute  these  three  efficiency  ratios  for  the 
joint  EJ  as  follows : 

BCD 

Ej= ,== ,  = (5) 

A  A  A 

Rule  III.  Divide  the  strength  of  the  weakest  sec- 
tion by  the  strength  of  the  solid  plate.  (See  Rute  I). 
The  result  is  the  efficiency  of  the  riveted  section. 

Thus  in  the  example  cited  we  have  seen  that  the 
strength  of  the  solid  plate  is  22,343  lb.,  that  its  strength 
between  rivet  holes  is  12,890  lb.,  that  the  shear- 
ing strength  is  16,332  lb.  and  that  the  crushing 
strength  of  the  plate  in  front  of  one  rivet  is  16,328  lb. 
Hence,  the  weakest  place  is  in  the  strength  between 
rivet  holes  and  consequently  the  efficiency  of  joint 
Ej  is 

12,890 

Ej  = —  =  .578. 

22,343 

Gage  Pressure  Necessary  to  Burst  the  Solid  Boiler 
Plate. — We  come  now  to  the  most  interesting  point  of 
our  analysis,  namely  to  compute  the  bursting  pressure 
of  the  solid  plate. 

In  the  discussion  of  the  strength  of  the  solid  boiler 
plate  we  found  that  the  force  of  steam  pressure  acting 
so  as  to  tear  the  boiler  plate  apart  longitudinally  would 
evidently  prove  most  disastrous  in  'bursting  the  solid 
boiler  plate.  Since  the  pressure  of  steam  exerts  itself 
equally  in  all  directions,  we  shall  compute  the  total 
pressure  available  in  this  particular  direction  as  this 
would  give  us  the  critical  pressure  for  our  present  con- 
sideration. 

If  the  boiler  is  of  length  1  inches  and  inner  diam- 
eter D  inches  the  area  of  steam  pressure  is  Dl.  Since 
now  the  boiler  gage  pressure  is  Ps  lb.  per  sq.  in.,  the 
total  pressure  of  the  steam  would  evidently  be 
P8D1  lb.  To  resist  the  boiler  tearing  apart  there  is  a 


STRENGTH  OF  BOILER  SHELLS 


153 


strip  of  boiler  metal  on  each  side  of  length  1  and  thick- 
ness t.  Hence  the  total  metallic  area  of  resistance  is 
2  It.  If  now  the  force  of  resistance  offered  by  the 
metal  is  St  lb.  per  sq.  in.,  we  have,  when  an  explosion 
or  bursting  apart  is  about  to  take  place,  that  this  re- 
sistive pressure  is  2  ltSt. 

Equating  these  two  pressures,  we  have 
PBDl  =  21tSt 


or     s  = 


2tSt 


D 


tst 

D/2 


(6) 


Thus  we  formulate. 

Rule  IV.  Multiply  the  thickness  of  the  plate  by 
the  tensile  strength  of  the  plate  and  divide  by  the 
radius  (one-half  of  the  diameter).  The  result  is  equal 
to  the  bursting  pressure  of  the  solid  plate. 


p  - 


A    DOUBLE    RIVETED    LAP   JOINT 

By  introducing  a  number  of  rows  of  rivets  for  riveted  lap  joints  the 
shearing  strength  and  the  crushing  strength  of  the  riveted  section 
are  proportionately  increased,  while  the  tensile  strength  of  the  net 
section  remains  the  same. 

In  the  example  previously  cited  we  now  compute 
the  bursting  pressure  of  the  solid  shell  of  the  boiler 
under  consideration  for  a  boiler  diameter  of  36  in.  as 

follows : 


154  FUEL  OIL  AND  STEAM  ENGINEERING 

0.25X55,000 


764  Ib. 


36/2 

This  means  that  a  gage  pressure  of  764  Ibs.  per 
sq.  in.  would  rupture  the  given  boiler  if  it  existed 
without  a  riveted  seam. 

Bursting  Pressure  of  the  Seam. — But  our  boiler 
under  consideration  would  evidently  burst  before  the 
bursting  pressure  of  the-^olid  plate  were  reached  for 
the  riveted  section  has/ weakened  its  total  strength. 
In  Rule  IV  we  found  that  the  efficiency  of  the  riveted 
joint  is  the  ratio  of  the  strength  of  the  weakest  point 
to  the  strength  of  the  solid  plate.  Hence  we  have 

•that;  the  gage  pressure   P  at    which  the    boiler    will 

-  probably  rupture  at  the  riveted  joint  is 

P  =  P6E, ...(7) 

Rule  V.  Multiply  the  bursting  pressure  of  the 
solid  plate  by  the  efficiency  of  the  joint.  This  result 
is  equal  tb  the  bursting  pressure  of  the  seam. 

Thus  since  the  efficiency  of  the  ^joint  Ej  is  found 
to  be  .578  and  the  bursting  pressure  Ps  of  the  solid 
plate  to  be  764  Ib.,  we  have  that  the  bursting  pressure 
P  of  the  jjoint  which  is  the  weakest  part  of  the  boiler 
construction  is 

p  =  psEj  =  764  X  .578  =  442  Ib. 

The  Safe  Working  Pressure. — Of  bourse  the  boiler 
is  never  allowed  to  operate  anywhere  near  this  burst- 
ing pressure.  A  factor  of  safety  is  insisted  upon. 
The  U.  S.  tables  are  based  upon  a  factor  of  safety  of 
3.5  for  drilled  holes  and  4.20  for  punched  holes,  which 
are  the  lowest  factors  allowed  in  any  civilized  coun- 
try* The  factor  in  most  European  countries  is  either 
5  or  6.  In  any  case,  if  factor  of  safety  f  is  used,  we 
have  that  the  working  pressure  Pw  is  found  from  the 
formula, '  ],. 
P 

Pw  =  -     -   -...(8) 

f 


STRENGTH  OF  BOILER  SHELLS 


155 


The  rule  advised  by  the  Hartford  Insurance  Com- 
pany's inspectors  is  as  follows : 

Rule  VI.  Divide  the  bursting  pressiire  of  the 
seam  by  the  following  safety  factors:  0  to  125  pounds, 
4.2;  from  125  to  150  pounds,  4.5 ;  150  pounds  or  over,  5. 
The  result  is  the  safe  working  pressure  under  which 
the  boiler  is  to  operate.  The  American  Society  of 
Mechanical  Engineers  in  their  Boiler  Code  require  a 
factor  of  safety  of  5  for  all  new  boilers. 


A    DOUBLE    RIVETED    BUTT    AND    DOUBLE    STRAP    JOINT 

In  general  the  butt  joint  doubles  the  shearing-  strength  of  the  joint 
while  the  net  tensile  strength  and  the  crushing  strength  of  the  joint 
remain  the  same  as  in  the  lap  joint  discussion. 

Thus  in  the  case  at  issue  the  safe  working  pres- 
sure Pw  becomes 

P  442 

Pw  =  -  —  105  Ib. 

f  4.2 

Recapitulating  the  discussion  of  the  six  rules,  we 
now  see  in  its  completeness  the  method  involved  in 
computing  the  safe  working  pressure  of  a  boiler.  In 
this  particular  instance  we  find  that  a  boiler  of  36  in. 
diameter,  with  y\  m-  plates  and  a  single  row  of  rivets 
spaced  l^j  in.  apart  may  safely  operate  under  105  Ib. 
pressure  (gage). 


156  FUEL  OIL  AND  STEAM  ENGINEERING 

Example  of  a  Lap  Joint,  Longitudinal  or  Circum- 
ferential, Double-Riveted. — By  similar  reasoning  we 
may  now  compute  the  efficiency  of  a  lap  joint  which 
is  double  riveted  whether  longitudinal  or  circum- 
ferential. Thus,  if  the  tensile  strength  of  a  boiler  is, 
stamped  55,000  Ib.  per  sq.  in.  with  thickness  of  plate 
5/16  in.,  pitch  of  rivets  2%  in.  diameter  of  rivet 
hole  %  in.,  we  have  by  applying  our  rules : 

A  =  2.875  X  0-3125  X  55,000  =  49,414. 
B=  (2.875  — 0.75)  0.3125x55,000  =  36,523. 
C  =  2  X  44,000  X  0.4418  =  38,878. 
D  =  2  X  0.75  X  0.3125  X  95,000  —  44,531. 

36,523 

..Ej  =  -  -=.739 

49,414 


CHAPTER  XIX 


FURNACES  IN  FUEL  OIL  PRACTICE 


Interior   of  a   Furnace,    show- 
ing Brickwork  and  Air 
Spacing 


ET  us  now  set  forth  the 
cycle  of  operations  neces- 
sary in  the  utilization  of 
crude  petroleum  as  an 
economic  factor  in  the 
production  of  steam.  The 
oil  in  a  heated  state  and 
under  pressure  must  be 
sprayed  into  a  heated 
compartment  or  furnace 
so  that  its  particles  are 
in  fine  globules  or  even 
in  a  gaseous  state.  Such 
an  operation  is  known 
as  atomization  and  this 
must  be  accomplished  in  an  efficient  and  thorough 
manner.  Three  methods  are  utilized  in  practice  to 
accomplish  this.  In  the  first  instance  steam  under 
pressure  is  mixed  with  the  oil  and  the  ingredients 
thus  shot  into  the  furnace.  In  the  second  instance 
compressed  air  is  used  to  accomplish  this  result,  and 
in  the  third  instance,  some  mechanical  device  or  phys- 
ical characteristic  of  the  oil  is  made  use  of  to  whirl 
or  thrust  the  oil  into  the  furnace  in  a  pulverized  or 
atomized  state.  Literally  hundreds  of  inventions  have 
been  made  to  effect  the  atomization  of  oil.  It  is  to  be 
remembered,  however,  that  in  the  consideration  of  fuel 
oil  economy,  the  furnace  and  its  efficient  construction 
are  after  all  the  real  factors  that  go  toward  economic 
fuel  consumption. 

Fuel  Oil  Furnace  Operation. — When  the  oil  is 
atomized,  it  must  be  brought  into  contact  with  the 
requisite  quantity  of  air  for  its  combustion,  and  this 
quantity  of  air  must  be  at  the  same  time  a  minimum 

157 


158 


FUEL  OIL  AND  STEAM  ENGINEERING 


to  avoid  undue  heat  losses  that  may  be  carried  away 
in  the  outgoing  flue  gases.  To  accomplish  this  result 
the  checkerwork  under  .the  burners  that  control  the 
admission  of  air  must  be  properly  designed.  The 
proper  quantity  of  air  admission  as  a  whole  is  con- 
trolled by  means  of  draft  regulation.  An  illustration 


THEORETICAL    DISPLAY    FOR    BRICKWORK    AND    AIR- 
SPACINGS 

In  the  nine  illustrations  shown  above  .are  graphically  displayed  the 
behavior  of  the  furnace  jflame  and  the  formation  of  carbon  for  va- 
rious arrangements  of  air  spacings  below  the  flame.  In  the  ninth 
instance  a  theoretically  perfect  flame  is  obtained. 

of  how  this  may  be  sensitively  controlled  was  shown 
in  the  chapter  on  the  fundamentals  of  furnace  opera- 
tion. 

To  accomplish  the  even  admission  of  air  into  the 
furnace  the  arrangement  of  the  check-board  of  brick- 
work below  the  flame  is  of  utmost  importance,  .other- 
wise unequal  heating  and  imperfect  combustion  is  sure 
to  follow.  Let  us  then  examine  a  chart  formulated  by 
E.  N.  Percy  of  the  Standard  Oil  Company's  technical 
staff.j  In  Fig/ 1  we  have  a  fan-s;haped  flame  with  open- 
ings between  all  the  bricks.  The  flame  .does  not  cover 
all  of  the  bricks,  hence,  no  matter  what  the  conditions 
are  there  will  be  an  excess  of  air  and  the  boiler  cannot 


FURNACES  159 

>vork  economically  since  it  costs  as  much  to  heat  air 
as  it  does  to  heat  water.  Fig.  2  shows  two  large  open- 
ings under  the  middle  of  the  flame ;  such  a  flame  will 
burn  hot  in  the  center  and  deposit  carbon  in  the  cort 
ners  as  shown.  In  Fig.  3  we  have  a  large  opening 
under  the  flame  flow;  this  arrangement  will  cause  the 
flame  to  tear  and  burn  intensely  at  the  center  while 
depositing  carbon  around  the  corners,  as  well  as  allowr 
ing  cold  air  to  rise  and  strike  the  boiler  directly.  The 
large  opening  in  Fig.  4  allows  quantities  of  oil  to 
escape  over  the  flame;  intense  combustion  will  take 
place  close  to  the  burner,  thereby  over-heating  it,  and 
at  the  same  time  the  flame  will  be  irregular  and 
ragged.  It  will  smoke  and  deposit  carbon  at  the  tips. 
The  transverse  openings  between  all  the  bricks  as 
shown  in  Fig.  5  allows  at  all  times  a  great  excess  of 
air  and  hence1  are  not  economic.  Fig.  6  shows  draft 
orifices  in  the  neighborhood  of  the  burner;  such  a 
flame  will  burn  clear  at  the  tips,  but  it  will  smoke  and 
deposit  carbon  near  the  burner.  The  longitudinal 
slots  in  Fig.  7  tend  to  tear  the  flame.  In  Fig.  8,  the 
arrangement  gives  a  broader  and  more  correctly 
shaped  flame,  still  an  excess  of  air  is  admitted  and 
cold  air  allowed  to  pass  up  against  the  boiler  because 
the:  draft  slots  extend  beyond  the  end  of  the  flame. 
Fig.  9  approaches  more  nearly  to  the  correct  arrange- 
ment of  bricks  and  the  correct  shape  of  flame  for  a 
flat  flarne  furnace. 

An  excellent  furnace  is  shown  on  page  162,  which 
sets  forth  the  floor  plan  of  a  back  shot  furnace  ar- 
rangetrient,  the  burner  being  set  in  a  recess  in  thi 
bridge  wall.  The  recess  is  made  large  enough  for  the 
removal  of  the  burner  and  piers  of  fire  brick  are  built 
on  the  furnace  floor  in  front  of  the  recess  so  that 
there,  is  an  opening  about  12  in.  by  9  in.,  through  which 
the  mixture  of  oil  and  steam  enters  the  furnace  from 
the  burner.  A  certain  quantity  of  air  enters  through 
the  same  opening,  being  drawn  in  by  the  force  of  the 
oil  and  steam.  A  bracke't  is  provided  to  hold  the 
burner  at  the  center  of  the  opening. 


160 


FUEL  OIL  AND  STEAM  ENGINEERING 


Air  openings  through  the  checker  work  on  the 
grates  commence  some  8  or  10  in.  from  the  burner, 
the  number  of  openings  and  the  width  increasing 
gradually  until  about  two  feet  from  the  burner  the 
openings  extend  across  the  full  width  of  the  furnace. 
There  are  no  openings  between  the  burners  near  the 
bridge  wall  so  that  no  air  can  enter  except  where  it 
comes  in  contact  with  the  atomized  oil.  The  fire  brick 


ARRANGEMENT  OF  AIR  SPACES  AND  GRATE  BARS  FOR 
FUEL  OIL  PRACTICE 

The  details  of  furnace  construction  have  more  to  do  with  efficient 
operation  in  the  burning  of  fuel  oil  than  anything  else.  In  each 
particular  installation  this  matter  should  receive  careful  attention. 
In  the  illustrations  are  shown  the  plan  and  elevation  of  the  air 
spaces  and  grate  bars  for  the  Parker  boiler  installation  for  the 
Fruitvale  Station  of  the  Southern  Pacific  Co.  This  boiler  developed 
an  evaporative  efficiency  of  83.69  per  cent  under  trial  test. 

piers  between  the  burners  become  hot  and  assist  in 
the  ignition  of  the  oil. 

The  distance  the  air  openings  are  extended  from 
the  burners  and  the  total  area  of  air  openings  depends 
on  the  draft  available  and  the  capacity  required  from 
the  boiler.  With  a  draft  of  .1  of  an  inch  in  the  fur- 
nace a  free  area  of  2^2  sq.  inches  per  rated  boiler 
horsepower  through  the  checker  work  and  J^  sq.  in. 
per  horsepower  around  the  burner,  making  a  total  of 
3  sq.  ins.  per  horsepower,  is  sufficient  to  operate  the 
boiler  from  its  rated  capacity  up  to  50%  overload. 


FURNACES 


161 


If  more  capacity  than  this  is  required  either  a  greater 
furnace  draft  must  be  provided  or  more  openings 
through  the  checker  work  must  be  installed  so  as  to 
increase  the  area.  The  amount  of  stack  draft  neces- 
sary to  maintain  .1  of  an  inch  furnace  draft  depends 
upon  the  type  of  boiler  and  the  capacity  at  which  it 
is  operated  as  this  will  determine  the  draft  loss 
through  the  boiler.  The  loss  of  draft  between  the 


A    FORMER    TYPE    OF    FURNACE 

In  this  view  the  floor  plan  of  a  back  shot  furnace  arrangement  is 
shown.  The  burner  is  set  in  a  recess  in  the  bridge  wall.  This  de- 
sign has  proven  of  high  order  in  central  station  installations  of  the 
West,  but  has  now  been  replaced  by  the  more  recent  type  shown 
on  the  following  page. 

breeching  and  the  furnace  usually  runs  from  about 
.15  of  an  inch  at  the  boilers'  rating  up  to  .8  or  one 
inch  at  double  rating. 

The  location  of  the  flame  can  be  varied  by  chang- 
ing the  height  of  the  burner  above  the  checker  work, 
this  height  usually  varying  from  4  in.  to  8  in.  or  9  in. 
The  character  of  the  flame  can  also  be  varied  by 
changing  the  distance  the  air  openings  extend  from 
the  burners.  It  is  customary  to  have  the  furthermost 
air  openings  about  four  or  five  feet  distant  from  the 
burner,  the  furnace  floor  beyond  this  point  being  cov- 
ered with  solid  brick.  By  bringing  the  air  openings 


162 


FUEL  OIL  AND  STEAM  ENGINEERING 


somewhat  farther  out  than  this  the  flame  can  be  made 
to  turn  up  or  by  having  the  air  openings  extended  out 
a  shorter  distance  the  flame  can  be  made  to  hug- 
closely  to  the  floor  of  the  furnace. 

The     Commercial    Furnace.  —  Illustrations     are 
shown  in  this  article  that  set  forth  the  check-board 


12'- 7 


ELEVATION 

AN  EXCELLENT  FURNACE  ARRANGEMENT 
Here  is  an  excellent  furnace  arrangement  designed  for  a  524  hp. 
boiler  with  standard  low  setting.  The  checker  work  on  the  grate 
bars  shown  in  shaded  area  represents  openings  2V2  by  3  in.  through 
the  brickwork.  The  free  area  through  the  checker  work  is  2.44  sq. 
in.  per  hp.,  around  the  burner  0.62  sq.  in.  per  hp.,  making  a  total 
free  area  of  3.06  sq.  in.  per  hp. 

of  brick  work  for  air  admission  in  the  commercial 
practice  of  boiler  economy.  Let  us  now  consider  all 
the  principal  factors  that  must  be  considered  in  pick- 
ing an  efficient  type  of  commercial  furnace. 

The  furnace  must  be  constructed  of  such  heat 
tested  brick-work  that  it  will  stand  up  under  the  high 
temperatures  developed  and  the  refractory  material 
of  which  it  is  composed  must  be  so  installed  as  to 
radiate  heat  to  assist  the  combustion  of  the  heated 
ingredients  of  the  fuel. 


FURNACES  163 

This  combustion  must  be  entirely  completed  be- 
fore the  gases  come  in  contact  with  the  heating  sur- 
faces of  the  boiler.  Otherwise,  the  flame  will  be 
extinguished,  possibly  to  unite  later  in  the  flue  con- 
nection or  in  the  stack.  This  means  that  ample  space 
must  be  provided  in  the  volumetric  proportions  of  the 
furnace  to  insure  this  combustion  before  the  gases 
begin  to  travel  upward  against  the  boiler  surfaces. 

Finally,  there  must  be  no  localization  of  the  heat 
on  certain  portions  of  the  heating  surfaces  or  trouble 
will  result  from  overheating  and  blistering.  This  is 
one  of  the  more  serious  defects  that  had  to  be  over- 
come in  the  earlier  days  of  fuel  oil  practice.  The 
burner  has  much  to  do  with  the  avoidance  of  this 
localization  activity. 

Regulation  of  Air. — The  area  of  air  openings 
through  the  checker-work  should  be  made  of  sufficient 
size  to  operate  the  boiler  at  the  maximum  capacity 
required  and  then  when  operating  at  lighter  loads  the 
air  supply  should  be  very  carefully  regulated.  There 
are  two  ways  by  which  the  air  can  be  regulated, 
namely,  by  the  damper  at  the  outlet  of  the  boiler  or 
by  the  ash  pit  doors.  If  the  air  is  regulated  by  the 
ash  pit  doors,  the  damper  being  left  wide  open,  there 
will  be  a  strong  draft  within  the  setting  tending  to 
cause  air  to  leak  in  through  all  the  cracks  in  the  brick 
work.  The  strong  draft  also  tends  to  pull  the  gases 
through  the  setting  by  the  shortest  cuts  so  that  a  thin 
stream  of  gases  flows  through  and  the  setting  is  not 
properly  filled  out  so  that  some  of  the  heating  surface 
is  not  swept  by  the  gases. 

If  on  the  other  hand  the  ash  pit  doors  are  left 
wide  open  and  the  air  is  regulated  by  partly  closing 
the  damper,  the  draft  inside  the  boiler  setting  is  very 
slight  so  that  the  air  leakage  is  reduced  to  a  minimum. 
There  is  little  force  tending  to  change  the  direction 
of  the  flow  of  the  gases  so  that  they  travel  of  their 
own  momentum  to  the  furthermost  corners  and  fill 
out  the  setting  completely,  thus  coming  in  contact 
with  all  the  heating  surface  of  the  boiler.  It  is,  there-- 
fore, much  better  to  regulate  the  air  by  means  of  the 


164 


FUEL  OIL  AND  STEAM  ENGINEERING 


damper  than  by  means  of  the  ash  pit  doors.  In  the 
case  of  very  light  loads,  however,  it  is  best  to  use  both 
the  damper  and  the  ash  pit  doors  because  if  the 
damper  alone  is  used  there  may  be  a  positive  pressure 
produced  in  the  upper  part  of  the  setting  causing  gas 
and  smoke  to  leak  out  into  the  fire  room. 

Importance  of  Air  Regulation. — The  regulation 
of  the  air  supply  is  one  of  the  most  important  things 
in  the  operation  of  oil  fired  boilers.  If  there  is  not 


PLAN    OF    BRICKWORK    AND    AIR    SPACINGS    IN     MARINE 
PRACTICE 

In  the  practical  application  of  the  theoretical  deductions  for  proper 
air  spacing-s,  commercial  designers  differ  somewhat  from  the  theo- 
retical reasoning-  involved.  In  this  illustration  is  shown  the  brick- 
work and  air-spacings  for  Scotch  marine  boilers  recommended  by  a 
prominent  company. 

enough  air  a  great  waste  of  fuel  may  occur  as  it  is 
possible  to  feed  the  oil  into  the  furnace  in  large  quan- 
tities and  if  there  is  not  enough  air  to  burn  it  the  oil 
and  gas  will  simply  pass  up  to  the  chimney  unburned. 
On  the  other  hand,  it  is  possible  to  waste  just  as  much 


FURNACES  165 

fuel  by  allowing  too  much  air  to  enter  the  furnace  as 
all  of  the  extra  air  is  heated  up  and  passes  out  at  the 
temperature  of  the  chimney  gases,  carrying  away  with 
it  an  enormous  amount  of  heat.  To  determine  accu- 
rately the  amount  of  air  required  for  the  best  condi- 
tions it  is  necessary  to  analyze  the  flue  gases.  Many 
plants,  however,  are  not  provided  with  the  apparatus 
necessary  for  this  and  in  such  cases  the  air  may  be 
regulated  with  a  fair  degree  of  accuracy  by  an  obser- 
vation of  the  smoke  discharged  from  the  stack.  For 
perfect  combustion  there  should  be  no  smoke  and  if 
any  smoke  appears  it  means  incomplete  combustion 
and  not  enough  air.  If  there  is  no  smoke,  however, 
it  does  not  follow  that  the  conditions  are  right,  as  no 
smoke  may  mean  either  just  the  right  amount  of  air 
or  a  large  excess  of  air.  To  properly  regulate  the  air, 
therefore,  if  the  boiler  is  operating  with  no  smoke  the 
damper  should  be  gradually  closed  until  a  light  gray 
smoke  just  begins  to  appear;  if  then  the  damper  is 
opened  very  slightly  this  smoke  will  be  barely  percep- 
tible and  the  conditions  for  the  most  economical 
operation  will  be  obtained. 

Service  For  One  Burner  Only. — Where  boilers 
having  more  than  one  burner  are  operated  at  very 
light  loads  it  is  necessary  at  times  to  have  only  one 
burner  in  operation,  the  other  burners  being  shut  off. 
For  such  service  as  this  it  is  very  desirable  to  have 
the  ash  pit  divided  into  as  many  sections  as  there  are 
burners  so  that  when  one  burner  is  shut  off  the  ash 
pit  door  opposite  that  door  can  be  closed  tight  and  no 
air  from  the  other  ash  pit  doors  will  enter  the  furnace 
opposite  that  particular  burner.  With  this  arrange- 
ment it  is  possible  to  operate  a  large  boiler  at  frac- 
tional loads  and  still  maintain  fairly  good  economy. 


CHAPTER  XX 

BURNER  CLASSIFICATION  IN  FUEL  OIL 
PRACTICE 

In  1902  and  1903  the  U.  S.  Naval  Fuel  Oil  Board 
made  an  exhaustive  inquiry  into  burners  of  various 
types.  In  their  report  a  classification  of  burners  was 
set  forth  which  comprehensively  details  the  funda- 
mentals of  various  types  of  burners  known  as  the 
drooling,  the  atomizer,  the  chamber,  the  injector,  and 
the  projector  types. 

In  the  drooling  type  the  burner  allows  the  oil 
to  drool  from  an  upper  opening  down  to  a  lower  open- 
ing from  which  the  steam  is  issuing.  An  atomizer 
burner  allows  the  oil  to  drop  directly  on  the  steam. 
The  chamber  or  inside  mixer  atomizes  the  oil  within 
the  burner  after  which  it  issues  from  an  orifice  of  the 
desired  form.  An  injector  burner  is  designed  pri- 
marily to  operate  without  a  pump  as  it  is  presumed 
that  the  oil  will  be  sucked  from  the  reservoir  by  the 
siphoning  or  injector-like  action  of  the  steam  jet 
inside.  In  the  projector  burners  the  steam  blows  the 
oil  from  the  tip  of  the  burner. 

Two  other  general  classifications  prevail  depend- 
ing upon  the  character  of  the  flame  emitted — namely, 
the  fan  tail  and  the  rose.  In  the  former  type  the 
burner  produces  a  flat  flame  while  in  the  latter  a  circu- 
lar flame  is  sent  forth. 

The  three  principal  types  of  burner  that  are 
encountered  in  central  station  practice  are,  however, 
known  as  the  inside  mixer,  the  outside  mixer,  and  the 
mechanical  atomizer. 

The  Inside  Mixer. — In  burners  of  this  class,  the 
steam  and  oil  come  into  contact,  and  the  oil  is  atom- 
ized inside  of  the  burner  itself,  and  the  mixture  issues 
from  the  burner  tip  ready  for  combustion  at  once. 
The  Hammel  burner  is  of  this  type. 

166 


BURNER  CLASSIFICATION 


167 


The  accompanying  cuts  illustrate  the  construc- 
tion of  this  burner.  Oil  enters  at  A,  flows  through 
D  into  the  mixing  and  atomizing  chamber  C ;  steam 
enters  at  B,  passes  through  F,  E,  and  then  through 
three  small  slots,  G,  H  and  I,  into  mixing  chamber 
C  where  it  meets  the  oil,  and  as  these  small  steam 
jets  cut  across  the  oil  stream  at  an  angle,  the  energy 


THE    INSIDE    MIXER  TYPE   OF   BURNER 

In  burners  of  this  type  the  steam  and  oil  come  into  contact  and  the 
oil  is  atomized  inside'  the  burner  itself.  The  mixture  then  issues 
from  the  burner  tip  ready  for  combustion.  The  Hammel  burner 
shown  in  the  illustration  above  is  of  this  type. 

of  the  steam  is  utilized.  The  burner  requires  for  its 
operation  about  2  per  cent  of  the  steam  generated  by 
the  boiler.  The  heavy  hydrocarbons  of  the  oil  are 
atomized,  the  light  hydrocarbons  are  vaporized,  and 
the  completed  mixture  issues  from  the  burner  and 
ignites  like  a  gas  flame.  In  normal  service  there  is 
no  tendency  to  carbonize,  and  the  only  way  in  which 
carbonizing  can  be  caused  is  by  turning  off  the  steam 
and  leaving  the  burner  filled  with  oil  instead  of  blow- 
ing it  out  before  shutting  down. 


168 


FUEL  OIL  AND  STEAM  ENGINEERING 


All  oil  is  usually  more  or  less  gritty  and  will 
cause  wear  of  some  part  of  the  burner.  This  is  pro- 
vided for  in  the  Hammel  burner — the  removable  plates 
K  K  can  be  quickly  replaced. 

The  Outside  Mixer. — In  the  outside  mixing  class 
the  steam  flows  through  a  narrow  slot  or  horizontal 


"On  Connection 

THE    OUTSIDE    MIXER    TYPE    OF    BURNER 

In  this  type  of  burner  the  steam  flows  through  a  narrow  slot  or 
horizontal  row  of  small  holes  in  the  burner  nozzle.  The  oil  flows 
through  a  similar  slot  or  hole  above  the  steam  orifice  and  is  picked 
up  by  the  steam  outside  of  the  burner  and  thus  atomized.  The 
Peabody  burner  which  is  shown  in  this  illustration  is  a  typical 
burner  of  this  type. 

row  of  small  holes  in  the  burner  nozzle ;  the  oil  flows 
through  a  similar  slot  or  hole  above  the  steam  orifice, 
and  is  picked  up  by  the  steam  outside  of  the  burner 
and  atomization  thus  accomplished.  The  Peabody 
burner  is  typical  of  this  class.  It  will  be  noted  that 
the  portions  of  the  burner  forming  the  orifice  may  be 
readily  replaced  in  case  of  wear  or  if  it  is  desired  to 
alter  the  form  of  the  flame. 

An  Example  of  the  Mechanical  Atomizer. — As  an 
illustration  of  one  of  the  many  interesting  types  of 
burners  that  produce  atomization  by  the  mechanical 
process,  let  us  consider  for  the  moment  the  rotary 
burner  of  the  Fess  System  Company.  The  mechanism 
that  accomplishes  the  atomization  is  operated  by  a 
small  electric  motor  as  shown  of  Y^  to  Vs  h.p.  The 
motor  operates  a  rotary  pump  through  a  worm  gear. 
This  pump  brings  the  crude  oil  from  the  storage  tank 
and  applies  it  to  the  burner,  which  is  placed  in  the 
center  of  the  fire  box.  The  burner  rotates  at  a  suf- 
ficient speed  to  thoroughly  atomize  the  oil  by  centri- 


BURNER  CLASSIFICATION  169 

fugal  force  and  by  the  proper  admission  of  air  a 
smokeless  flame  is  produced  equally  distributed 
throughout  the  fire  box. 


A    MECHANICAL    TYPE    OF    ATOMIZER 

Many  types  of  mechanical  atomizer  may  be  seen  upon  the  market 
in  which  various  physical  laws  are  made  use  of  to  accomplish 
atomization.  In  the  mechanism  shown  in  the  illustration,  which 
is  that  of  the  Fess  System  Company,  the  burner  is  caused  to 
rotate  at  a  sufficient  speed  to  thoroughly  atomize  the  oil  by  cen- 
trifugal force.  By  the  proper  admission  of  air  a  smokeless  flame 
is  produced,  equally  distributed  throughout  the  fire-box. 


The  Home-Made  Type  of  Burner. — Patented  oil 
burners  are  practically  unknown  in  the  oil  fields. 
Every  operator  makes  his  own  burner  out  of  ordinary 
fittings.  The  construction  varies  somewhat  depending 
upon  the  ideas  of  the  maker  and  the  quality  of 
oil  burned.  The  general  principle  of  the  burner  is 
illustrated  in  the  sketch.  No  oil  pumps  are  used,  the 
oil  being  supplied  by  gravity  from  a  tank  set  from  6 
to  10  feet  above  the  ground. 

An  important  peculiarity  of  the  burner  is  that  it 
is  self-regulating  to  a  great  extent.  The  impact  of 
the  jet  of  steam  issuing  from  the  inner  pipe  produces 
a  back  pressure  on  the  oil  issuing  from  the  annular 
space  between  the  pipes.  If  the  steam  valve  is  adjusted 
for  good  atomization  any  increase  of  the  steam  pres- 
sure will  cause  more  steam  to  flow  through  the  inner 
pipe.  This  will  increase  the  back  pressure  at  the  tip 
and  choke  back  the  oil  coming  from  the  annular  space, 
thus  decreasing  the  fire. 

If,  on  the  other  hand,  the  steam  pressure  drops, 
the  back  pressure  at  the  tip  is  decreased,  more  oil 
will  flow  and  the  fire  will  be  increased. 


170 


FUEL  OIL  AND  STEAM  ENGINEERING 


This  type  of  burner  is  sensitive  to  variations  in 
steam  pressure.  As  the  steam  pressure  goes  up,  the 
fire  is  cut  down  until  a  point  is  reached  at  which  the 
fire  becomes  spasmodic  or  "bucks." 

While  this  self  regulating  feature  helps  to  main- 
tain constant  pressure  on  the  boiler,  it  is  not  econom- 
ical because  as  the  steam  pressure  increases,  thus 
diminishing  the  quantity  of  oil,  the  quantity  of  steam 


THE    HOMEMADE    BURNER 

This  ingenious  type  of  homemade  burner  is  a  product  of  the  oil 
fields.  The  impact  of  the  jet  of  steam  which  issues  from  the 
inner  pipe  produces  a  back  pressure  on  the  oil  issuing  from  the 
annular  space  between  the  pipes,  thus  making  the  burner  self- 
regulating  to  a  great  extent. 

increases  with  the  pressure.  Thus,  the  less  oil  is 
burned  the  more  steam  is  used  for  atomizing,  which 
is  just  the  opposite  of  what  it  should  be. 

Another  peculiarity  of  the  burner  is  that  it  will 
begin  to  atomize  when  the  steam  pressure  is  less  thin 
a  pound  above  atmosphere.  As  soon  as  a  sizzle  is 
heard  issuing  from  the  steam  pipe,  the  burner  wiil 
make  a  fairly  good  fire. 

Front  Shot  and  Back  Shot  Burners 
There  are  two  general  methods  by  which  B  &  W 
or  Stirling  boilers  can  be  fired  with  oil,  known  as  the 


BURNER  CLASSIFICATION  171 

front  shot  and  the  back  shot.  With  the  front  shot  ar- 
rangement the  burner  is  introduced  through  the  front 
wall  and  the  flame  is  shot  back  towards  the  bridge 
wall.  With  the  back  shot  arrangement  the  burner  is 
placed  at  the  bridge  wall  and  the  flame  shoots  forward. 
Owing  to  the  fact  that  the  tubes  are  inclined  down- 
wards toward  the  rear,  the  back  shot  arrangement 
gives  a  larger  furnace  volume  at  the  end  of  the  furnace 
farthest  from  the  burner.  This  is  of  considerable  ad- 
vantage in  permitting  the  gases  to  expand  and  cause 
perfect  combustion.  Another  advantage  of  the  back 
shot  burner  with  the  B  &  W  boiler  is  that  the  flame 
is  shot  forward  and  comes  in  contact  with  the  front 
end  of  the  tubes,  whereas  with  the  front  shot  burner 
the  gases  are  forced  back  close  to  the  front  baffle  and 
do  not  have  any  tendency  to  fill  the  front  pass  of  the 
boiler.  This  condition  is  illustrated  in  the  adjoining 
cuts.  The  result  is  that  with  the  front  shot  burner  a 
considerable  portion  of  the  heating  surface  is  by-passed 
by  the  gases  and  is  therefore,  non-effective.  With  the 
Stirling  boiler,  however,  while  the  back  shot  burner 
gives  the  best  furnace,  the  front  shot  burner  causes 
greater  effectiveness  of  heating  surface. 

Quantity  of  Steam  Required. — The  regulation  of 
the  quantity  of  steam  used  for  atomizing  the  oil  is 
a  matter  of  very  great  importance,  for  if  more  steam 
is  used  than  is  actually  needed  there  is  not  only  a 
waste  of  the  excess  quantity  of  steam  but  also  there 
is  a  loss  of  the  heat  required  to  raise  the  temperature 
of  this  extra  steam  up  to  the  temperature  of  the 
escaping  gases.  With  careless  operation  the  quantity 
of  steam  supplied  to  the  burners  sometimes  amounts 
to  as  much  as  5%  of  the  total  steam  generated  by  the 
boiler,  whereas  with  proper  care  in  operating,  this 
quantity  can  be  reduced  below  1%.  A  simple  way  to 
adjust  the  quantity  of  steam  supplied  is  to  gradually 
close  down  on.  the  steam  valve  to  the  burner  until 
drops  of  oil  fall  on  the  furnace  floor.  The  drops  burn 
and  scintillate  and  can  be  readily  seen  and  this  scin- 
tillation indicates  that  there  is  not  sufficient  steam 
to  atomize  the  oil.  As  soon  as  this  point  is  reached 


172 


FUEL  OIL  AND  STEAM  ENGINEERING 


B.   &   W.    BOILER    WITH    FRONT   SHOT    OIL    BURNER 

With  this  furnace  arrangement  the  flame  does  not  fill  out  the  first 
pass,  so  the  front  end  of  the  tubes  do  not  do  their  share  of  the 
work. 

the  steam  valve  should  be  opened  just  enough  to  stop 
the  scintillating  action.  This  method  will  insure  suf- 
ficient steam  being  supplied  but  no  more  than  neces- 
sary. 

The  quantity  of  steam  supplied  to  the  burner 
bears  an  important  relation  to  the  furnace  arrange- 
ment and  the  air  supply,  as  both  the  shape  and  char- 
acter of  the  flame  change  when  the  quantity  of  steam 
is  varied.  With  too  much  steam  an  intense  white 
flame  is  produced  which  has  a  tendency  to  cause  local- 
ization of  heat  on  the  brickwork  or  the  tubes.  With 
the  proper  amount  of  steam  and  correct  air  regulation 
a  soft  orange-colored  flame  is  produced  which  fills 
out  the  furnace  and  has  a  good  deal  the  appearance 
of  a  flame  from  a  soft  coal  fire.  This  flame  will  some- 
times appear  smoky  in  the  furnace  but  the  smoke 
disappears  before  the  gases  reach  the  stack.  It  is, 
therefore,  unnecessary  to  have  an  absolutely  clear 
flame  in  the  furnace. 

It  is  not  a  difficult  matter  for  an  experienced  man 
in  charge  of  the  boiler  plant  to  properly  adjust  the 
steam  and  oil  valves  so  as  to  get  the  right  amount  of 
steam.  It  is  often  very  difficult,  however,  to  get  the 


BURNER  CLASSIFICATION 


173 


B.   &   W.    BOILER   WITH    BACK   SHOT   OIL    BURNER 

With  this  furnace  arrangement  the  gases  have  ample  volume  in 
which  to  burn,  and  they  distribute  themselves  over  the  entire  first 
pass,  resulting  in  efficient  operation. 

firemen  to  use  sufficient  care  in  making  these  adjust- 
ments. A  simple  method  of  preventing  too  much 
steam  being  used  for  atomizing  where  boilers  are 
operated  at  a  fairly  steady  load  is  to  provide  a  disc 
with  a  small  hole  in  it,  in  the  steam  to  burner  line. 
This  disc  restricts  the  quantity  of  steam  that  can  pass 
through  to  the  burner.  The  size  of  the  hole  in  the 
disc  depends  on  the  steam  pressure  used  and  on  the 
capacity  required  from  the  boiler  and  must  be  deter- 
mined by  experiment.  In  a  plant  using  200  Ib.  steam 
pressure  a  hole  5/16  in.  in  diameter  has  been  found 
large  enough  to  supply  all  the  atomizing  steam  re- 
quired for  a  600  h.p.  boiler.  A  by-pass  should  be 
provided  on  the  steam  line  so  as  to  pass  steam  around 
the  disc  in  case  it  is  found  necessary  to  force  the  boiler 
at  any  time  above  its  normal  capacity.  By  providing 
the  by-pass  with  a  valve  having  a  rising  stem  it  can 
be  seen  at  a  glance  whether  the  valve  is  open  or  shut. 

The  quantity  of  steam  required  for  atomizing 
depends  largely  on  the  temperature  of  the  oil.  The 
hotter  the  oil  the  less  steam  is  required.  In  central 
station  work  the  oil  should  be  heated  up  to  about  180° 


174 


FUEL  OIL  AND  STEAM  ENGINEERING 


STIRLING    BOILER    WITH    FRONT    SHOT    OIL    BURNER 

With  this  furnace  arrangement  the  tubes  are  swept  by  the  hot 
gases  for  their  full  length,  but  this  advantage  is  gained  at  the 
expense  of  furnace  efficiency  owing  to  the  smaller  volume  available 
as  combustion  chamber. 

Fahrenheit  on  the  pressure  side  of  the  pumps,  the 
pressure  carried  running  from  40  to  60  Ibs. 

Number  of  Men  Required  for  Operating  Oil  Fired 
Boilers. — The  number  of  men  required  to  operate 
boilers  fired  by  oil  is  much  less  than  the  number 
required  to  operate  a  coal  burning  plant.  In  an  oil 
burning  central  station  a  fireman  can  operate  six  or 
seven  large  boilers  having  three  oil  burners  each,  and 
in  addition  attend  to  the  feeding  of  the  boilers  with 
water.  In  other  words,  a  plant  having  26  or  28  boilers 
would  require  only  four  firemen  on  a  watch  besides 
a  man  to  look  after  the  feed  pumps,  oil  pumps  and 
keep  records  of  oil  consumption,  temperatures,  etc. 

Caution. — In  operating  oil  fired  boilers  it  is  ex- 
tremely important  to  avoid  any  accumulation  of  gas 
in  the  boiler  setting,  consequently,  no  oil  should  be 


BURNER  CLASSIFICATION 


175 


STIRLING    BOILER   WITH    BACK   SHOT   OIL    BURNER 

This  furnace  arrangement  gives  a  splendid  furnace  with  large  vol- 
xime,  but  the  gases  come  in  contact  with  only  about  one-third  of 
the  tubes  in  the  front  bank,  so  that  the  effectiveness  of  the  heating 
surface  is  impaired. 

allowed  to  get  into  the  furnace  unless  there  is  a  fire 
to  ignite  it  and  no  more  oil  should  be  fed  into  the 
furnace  than  can  be  burned  with  the  available  quan- 
tity of  air  and  atomizing  steam.  Any  accumulation 
of  gases  inside  the  settings  is  liable  to  cause  explo- 
sions which  may  result  in  serious  damage. 


CHAPTER  XXI 

THE   GRAVITY   OF  OILS  IN   FUEL   OIL 
PRACTICE 

Fuel  oil  is  classified,  marketed,  and  designated  by 
its  gravity.  Gravity  is  denoted  in  two  distinct  ways. 
The  scientific  method  of  notation  is  known  as  the 

"specific  gravity,"  which  is 
the  ratio  of  the  weight  of 
a  given  volume  of  the  oil 
to  that  of  an  equal  volume 
of  pure  water.  There  has, 
however,  grown  up  in  prac- 
tice an  empirical  method 
of  representing  the  gravity 
of  oil  by  what  is  known  as 
the  B  a  u  m  e  scale.  This 
scale  has  two  separate  and 
distinct  formulas  for  its 
conversion  to  specific  grav- 
ity readings.  One  formula 
is  for  liquids  heavier  than 
water  and  the  other  for 
liquids  lighter  than  water. 
In  each  instance  the  scale 
is  graduated  to  100  degrees 
and  overlaps  10  degrees. 

Antoine   Baume,   a 
French   chemist   of   the 
eighteenth  century,  distin- 
guished for  his  success  in 
Baume  Hydrometers  the  practical  application  of 

the  science,  was  the  inven- 
tor of  the  so-called  Baume  scale  now  universally 
adopted  in  fuel  oil  practice  for  denoting  the  gravity 
of  crude  petroleum. 

176 


GRAVITY  OF  OILS  177 

The   Scale  for   Liquids   Heavier  Than  Water. — 

Baume  hit  upon  a  unique  plan  for  the  establishment 
of  his  scale.  Certain  fixed  points  were  first  determined 
upon  the  stem  of  the  instrument.  The  first  of  these 
was  found  by  immersing  the  hydrometer  in  pure 
water,  and  marking  the  stem  at  the  level  of  the  sur- 
face. This  formed  the  zero  of  the  scale.  Fifteen 
standard  solutions  of  pure  common  salt  in  water  were 

then  prepared,  containing  respectively  1,  2,  3 15 

per  cent  (by  weight)  of  dry  salt.  The  hydrometer 
was  plunged  in  these  in  order  and  the  stem  having 
been  marked  at  the  several  surfaces,  the  degrees  so 
obtained  were  numbered  1,  2,  3 15. 

The  instrument  thus  adapted  to  the  determination 
of  densities  exceeding  that  of  water  was  called  the 
hydrometer  for  salts. 

Expressed  mathematically  in  its  relationship  with 
the  specific  gravity  S,  the  Baume  degree  reading  B 
becomes  for  liquids  heavier  than  water : 

145 

S—  - (1) 

145— B 

The   Scale   for   Liquids   Lighter   Than   Water.— 

Since  practically  all  grades  of  crude  petroleum  are 
lighter  than  water,  we  are  most  interested  in  the 
method  of  expression  for  this  latter  phase  of  gravity 
denotation. 

The  original  Baume  hydrometer  intended  for 
densities  less  than  that  of  water,  or  the  hydrometer 
for  spirits,  as  it  was  called,  was  constructed  on  a  sim- 
ilar principle  to  that  for  the  hydrometer  of  salts  above 
described.  The  instrument  was  so  arranged  that  it 
floated  in  pure  water  with  most  of  the  stem  above  the 
surface.  A  solution  containing  10  per  cent  of  pure 
salt  was  used  to  indicate  the  zero  of  the  scale,  and  the 
point  at  which  the  instrument  floated  when  immersed 
in  distilled  water  at  10°  R  or  54^°  F.  was  numbered 
10.  Equal  divisions  were  then  marked  off  upwards 
along  the  stem  as  far  as  the  50th  degree. 


178  FUEL  OIL  AND  STEAM  ENGINEERING 

The  Confusion  in  Expression  for  Specific  Grav- 
ity and  Baume  Readings.  —  Modern  gravities  are  ex- 
pressed for  liquid  temperatures  of  60°  F.  instead  of 
54^°  F.  as  above  set  forth.  This  fact  together  with 
other  inconsistencies  and  errors  in  observation  have 
led  to  the  invention  of  some  seventeen  different  math- 
ematical expressions,  by  various  investigators  and 
scientific  bodies,  to  properly  set  forth  a  relationship 
between  specific  gravity  and  Baume  readings  for 
liquids  lighter  than  water.  The  contest  has  simmered 
down  to  two  equations  in  American  practice. 

The  formula  that  is  used  by  Tagliabue  in  his 
tables,  and  that  has  been  adopted  by  the  Petroleum 
Association,  which  embraces  within  its  membership 
practically  all  of  the  oil  refiners  of  the  United  States, 
is  as  follows  : 

141.5 

(2) 


131.5  +  B 

On  the  other  hand,  in  Kent's  Mechanical  Engi- 
neer's Handbook  is  found  a  formula  which  has  been 
adopted  by  the  United  States  Bureau  of  Standards 
and  which  receives  the  strong  endorsement  of  the 
mechanical  and  electrical  engineers  of  the  Pacific 
Goast.  The  formula  is  : 

140 

(3) 


130  +B 

The  Limitations  of  the  Hydrometer.  —  The  hydro- 
meter method  of  ascertaining  the  gravity  .of  crude 
petroleum  is  at  best  only  approximate,  a3  one  may 
readily  surmise.  In  order  then  to  ascertain  the  gravity 
of  oil  with  scientific  accuracy,  a  more  refined  method 
is  necessary.  This  is  usually  accomplished  by  deter- 
mining the  specific  gravity  of  the  oil  with  whatever 
moisture  content  it  may  contain  by  means  of  an  actual 
water  equivalent  comparison,  and  then  converting  this 
into  degrees  Baume..  This  roundabout  method  once 
again  emphasizes  the  uselessness  of  employing  the 
Baume  scale.  If  the  moisture  content  of  the  oil  has 


GRAVITY  OF  OILS  179 

been  ascertained,  a  computation  is  then  made  in  order 
to  arrive  at  the  actual  specific  gravity  or  Baume  read- 
ing for  the  moisture  free  oil. 

The  Method  of  the  Westphal  Balance  for  Exact 
Measurement. — Let  us  then  examine  in  detail  such  a 
method.  The  Westphal  balance  is  a  convenient  and 
accurate  method  by  which  the  specific  gravity  of  fuel 
oil  may  be  obtained  to  four  decimal  points.  As  shown 
in  the  illustration,  the  apparatus  necessary  consists  of 
a  balance  arm,  supported  on  knife  edges,  from  one  end 
of  which  is  hung  a  glass  bulb,  the  other  end  being 
counter-weighed.  Along  the  balance  arm  are  nine 
notches,  the  hook  supporting  the  glass  bulb  being  in 
the  position  of  the  tenth  notch.  The  glass  bulb  has  a 
displacement  of  exactly  five  grams  of  pure  water  at 
4°C,  which  is  the  point  of  maximum  density  of  water, 
the  density  for  which  scientific  gravity  comparisons 
are  made.  Hence  if  the  bulb  above  described  were  so 
immersed  in  water  at  4°C.  a  five  gram  weight  would 
establish  equilibrium  if  hung  from  the  hook.  This 
would  indicate  a  specific  gravity  of  1.0000. 

The  zero  point  of  the  balance  is  adjusted  by  turn- 
ing a  thumb  screw,  which  forms  one  point  of  the  three 
point  support  shown  in  the  figure,  until  the  pointers 
are  opposite  each  other  before  the  bulb  is  immersed. 
For  specific  gravities  less  than  1 .0000  the  five  gram 
rider  called  the  unit  weight  is  hung  in  a  notch  such 
that  equilibrium  is  nearly  reached,  never  exceeded. 
This  gives  the  first  decimal  place.  The  1/10,  1/100.  and 
1/1000  unit  weights  are  then  hung  respectively  in 
notches  so  that  equilibrium  is  finally  established.  The 
specific  gravity  is  then  read  directly  to  four  decimal 
places  by  noting  the  notches  in  which  the  riders  hang, 
commencing  with  the  largest  rider.  Thus  when  the  unit 
weight  hangs  in  the  ninth  notch,  the  l/10th  weight  in 
the  sixth  notch,  the  1/100  weight  in  the  seventh  notch, 
and  the  1/1000  weight  in  the  third  notch,  the  specific 
gravity  is  evidently  .9673. 

Details  of  Procedure. — Before  proceeding  with  a 
gravity  determination,  the  oil  sample  should  be  al- 
lowed to  stand  in  the  laboratory  several  hours  in  order 


180  FUEL  OIL  AND  STEAM  ENGINEERING 

that  any  drops  of  water  in  the  oil  may  settle.  A  small 
quantity  is  then  poured  from  the  sample  can  into  a 
suitable  glass  jar.  The  Westphal  balance,  having  been 
dusted  with  a  soft  brush,  is  then  adjusted  to  equilib- 
rium and  the  specific  gravity  of  the  sample  obtained. 


A   COMMERCIAL    BALANCE    FOR    DETERMINING    SPECIFIC 
GRAVITY    OF    OIL 

The  common  hydrometer  is  not  of  sufficient  accuracy  to  determine 
the  specific  gravity  of  oil  used  in  fuel  oil  tests.  A  simple  and 
accurate  method  for  such  determination  is  accomplished  by  the 
employment  of  a  Westphal  Balance  as  shown  in  the  illustration. 
The  specific  gravity  is  first  ascertained  by  comparison  of  the  oil 
\vitn  a  water  standard  and  then  by  means  of  the  mathematical 
relationship  connecting  specific  gravities  and  Baume  readings,  the 
latter  gravity  reading  is  ascertained. 

The  temperature  is  also  ascertained  by  means  of  the 
thermometer  inserted  in  the  oil  sample.  Since  specific 
gravities  of  fuel  oil  are  by  common  practice  referred  to 


GRAVITY  OF  OILS  181 

at  a  temperature  of  60°F.,  it  is  now  necessary  to  make 
a  second  determination  at  a  temperature  differing  by 
15°  to  20°F.  from  the  first,  in  order  that  we  may  have 
sufficient  data  with  which  to  compute  what  the  gravity 
would  be  at  60°  F.  temperature. 

To  take  this  second  reading  the  temperature  of 
the  sample  in  the  jar  may  be  raised  by  immersion  in 
a  water  bath.  In  doing  this  great  care  must  be  taken 
to  allow  no  water  to  get  into  the  oil. 

Computations  Involved.  —  Let  us  next  illustrate 
the  computations  involved  in  a  gravity  determination. 
Let  us  assume  that  by  means  of  the  Westphal  balance, 
the  oil  sample  is  seen  to  have  a  specific  gravity  (SJ  of 
.9644,  at  a  temperature  (tx)  of  68.9°F.,  and  a  specific 
gravity  (S2)  of  .9587  at  a  temperature  (t2)  of  86.6°  F. 
Since  the  specific  gravity  has  changed  (S±  —  S2)  over 
a  temperature  change  of  (t^_  —  t2)  the  change  for  1°F. 

(Sx  —  S2) 

would  be   -  —  ;     This  change  in  specific  grav- 


ity  for  1°F.  is  the  coefficient  of  expansion  (Ce),  for  the 
oil  and  may  be  expressed  by  the  formula 

(Si  —  S,) 

C.  =  -  -     ..............  ........  .....      (4) 

(t,  -  -  t2) 

In  the  particular  case  then  we  now  find  that 

.9644  —  .9587 

Ce  =  --  :  -  =  —  .000322. 
68.9  —  86.6 

The  coefficient  is  thus  seen  in  this  case  to  represent 
an  intermediate  value,  for  in  practice  we  find  that  in 
different  oils  Ce  varies  from  (—.00027)  to  (—.00042). 
From  the  fundamental  definition  of  the  coefficient 
of  expansion  it  is  now  seen  that  at  60°  F.,  the  specific 
gravity  becomes 

S  =  S1  +  Ce  (60-  1.)   .......  ..............   (5) 


182  FUEL  OIL  AND  STEAM  ENGINEERING 

Consequently  by  making  the  proper  substitutions  for 
the  case  cited  we  find  that  the  numerical  value  of  the 
specific  gravity  of  this  oil  sample  for  60°F.  is 

S  =  .9644  +  [—  .000322  X  (—  8.9)  ]  =0.9673 

In  order  to  convert  this  specific  gravity  to  the 
Baume  scale  we  now,  by  substituting  in  formula  given 
above  for  such  conversion,  find  that 

141.5 

B=-  -131.5  —  14.78° 

0.9673 

Assuming  that  this  particular  oil  sample  has  been 
found  to  contain  0.5  per  cent  by  weight  of  moisture 
and  0.484  per  cent  by  volume,  let  us  now  see  how  we 
should  find  the  specific  gravity  of  the  dry  oil.  Let  Vw 
represent  the  percentage  of  water  by  volume  and 
Sw,  S0,  Sm  represent  respectively  the  specific  gravity 
of  the  water,  dry  oil,  and  moisture.  Then  we  may 
write  the  following  relationship  : 

100  —  Vw  Vw 

Sm  =  S0(-  -)+Sw(-    -)  ........  (6) 

100  100* 

From  scientific  tables  we  find  that  Sw  at  60°  F.  has 
a  value  of  .9990,  and  from  the  Westphal  balance  Sm 
has  been  found  to  be  .9673.  By  transforming  the 
formula  above  it  is  seen  that 

vw 


v 

1.00- 


100 

...................  (7) 


100 

Consequently  S0  may  now  be  computed  numerically. 
.9673  —  .00484  X  -9990 


1.00  —  .00484 


—  .9671 


GRAVITY  OF  OILS  183 

If  it  is  desirable  to  ascertain  the  Baume  reading 
for  the  dry  oil,  we  next  ascertain  its  value  from  the 
above  relationship  of  specific  gravity  and  the  Baume 
scale  from  equation  (2). 

141.5  141.5 

B=-  -131.5  —  -  -131.5  =  14.8° 

S  .9671 

According  to  formula  (3)  this  Baume  reading 
would  of  course  be  computed  as  follows: 

140  140 

B=-  -130  = 130—14.8° 

S  .9671 

When  a  large  quantity  of  oil  is  to  be  purchased 
and  it  is  desirable  to  carry  the  Baume  reading  to  still 
further  decimal  points,  the  two  formulas  will  not  of 
course  check;  hence,  one  or  the  other  of  these  form- 
ulas should  be  agreed  upon  prior  to  a  purchase  of  any 
magnitude. 


CHAPTER  XXII 


MOISTURE  CONTENT  OF  OILS 

From  our  previous  discussion  of  steam  genera- 
tion in  the  modern  central  station  it  was  found  that 

something  over  a  thousand 
heat  units  are  necessary  to 
convert  water  at  ordinary 
temperatures  into  saturated 
steam.  When  moisture 
appears  in  the  oil  used  for 
heat  generating  purposes 
in  the  furnace  it  is  evident, 
then,  that  large  heat  losses 
may  thereby  be  involved. 
For,  not  only  must  this 
AN  ELECTRICALLY  DRIVEN  moisture  be  converted  into 
OIL  CENTRIFUGE  saturated  steam,  but  this 

in   this   centrifug-e    the   four  steam  itself  must  be  super- 

-  heated  to  the  temperature 
of  the  outgoing  chimney 
thus  dissipating 
energies  that  should  go 
toward  steam  generation  in 
the  boiler. 

Hence  the  water  involved  in  fuel  oil  composition 
is  a  dead  loss  which  should  be  avoided  as  far  as  pos- 
sible. Settling  tanks  accomplish  much  in  drawing  off 
the  water  content,  but  when  the  water  appears  in  the 
oil  as  an  emulsion  it  is  almost  impossible  to  com- 
mercially segregate  it  from  the  oil.  Since,  then,  all 
fuel  oils  contain  a  certain  amount  of  moisture,  the 
careful  determination  of  its  exact  proportions  often 
becomes  an  important  problem  in  efficient  steam 
engineering  performance. 

Summary  of  Methods  Employed  in  Determining 
the  Moisture  Content! — There  are  ten  methods  by 


uated — are  caused  to  rotate  by 
electric  power  and  the  water 
thus  caused  to  separate  from  gases 
the  oil.  The  consequent  meas- 
urement of  the  moisture  pres- 
ent is  then  easily  ascertained. 


184 


MOISTURE  CONTENT  185 

which  the  moisture  content  of  oil  can  be  ascertained 
with  approximate  accuracy.  For  detailed  information 
on  this  subject  the  reader  is  referred  to  Technical 
Paper  No.  25  of  the  United  States  Bureau  of  Mines 
entitled,  "Methods  for  the  Determination  of  Water  in 
Petroleum  and  its  Products."  These  methods  may  be 
briefly  summarized  as  follows: 

The  moisture  content  of 'heavy  oils  and  greases 
may  be  (approximately)  ascertained  by  (the  loss  of 
weight  due  to  heating.  ) 

The  moisture  content  of  oil  may  be  approxi- 
mately obtained  by  diluting  a  sample  with  a  sulphate 
and  then  causing  separation  by  action  of  gravity.  A 
diluent  is  to  be  avoided  in  this  process,  as  inac- 
curacies are  liable  to  be  introduced. 

Again  by  diluting  with  a  solvent  and  separating 
the  moisture  content  by  means  of  a  centrifuge, !  the 
moisture  content  is  determined  with  a  slightly  greater 
degree  of  accuracy  than  by  either  of  the  above 
methods. 

By  treating  a  sample  with  calcium  carbide, 
another  convenient  method  is  also  arrived  at,  and  its 
accuracy  is  approximately  within  3%  of  the  water 
percentage  if  care  is  observed.  The  sample,  too,  may 
be  treated  with;sodium]and  a  convenient  and  accurate 
method  results. 

A  color  comparator  is  sometimes  used,  but  the 
method  is  only  approximate,  as  is  also  the  method  of 
treating  a  sample  with  normal  acids.  The  ( electrical 
treatment,  on  the  other  hand,  is  successful  in  break- 
ing up  an  emulsion  on  a  commercial  scale,  or  reducing 
the  water  content  of  an  oil  to  such  a  condition  that  it 
may  be  successfully  treated  in  some  other  manner. 
An  emulsion  is  a  physical  condition  of  the  oil  and 
water  wherein  the  water  is  held  in  such  intimate 
contact  with  the  oil  ingredients  as  not  to  be  readily 
separated  by  gravity  or  other  ordinary  means. 

Again,  too,  (distilling  a  sample  mixed  with  a  non- 
miscible  liquid;  proves  accurate  to  .033  grams  of  water 
per  100  cc.  of  benzine  and  oil  in  the  distillate. 


186  FUEL  OIL  AND  STEAM  ENGINEERING 

The  most  reliable  method,  however,  is  that 
accomplished  by  directly  (distilling^off  the  water.  This 
method  is  convenient  and  accurate  to  about  .003  grams 
of  water  in  the  distillate,  if  the  water  is  cooled  to 
about  35°  F. 

The   Approximate   Method   of    Treatment. — The 

method  hinted  at  above  wherein  the  sample  is  treated 
by  a  foreign  agent  will  now  be  briefly  set  forth,  since 
such  a  preliminary  determination  often  proves  suffi- 
ciently accurate  for  the  issues  involved. 

The  method  here  outlined  is  especially  applicable 
for  the  lighter  'oils.  A  burette  graduated  into  200 


A  GOETZ  ATTACHMENT   FOR   WATER    DETERMINATION 

By  attaching  the  pipe  shown  in  the  lower  part  of  the  figure  to 
a  faucet,  sufficient  power  is  obtained  from  the  city  main  to  cause 
the  rapid  rotation  of  the  two  arms  shown  in  the  figure.  This  high 
rotative  speed,  due  to  the  centrifugal  force  developed,  causes  the 
separation  of  the  moisture  from  the  oil. 

divisions  is  filled  to  the  100  mark  with  (gasoline,  land 
the  remaining  100  divisions  with  the  oil,  which  should 
be  slightly  warmed  before  mixing.  The  two  are  then 
shaken  together  and  any  shrinkage  below  the  200 
mark  filled  up  with  the  oil.  The  mixture  should  then 
be  allowed  to  stand  in  a  warm  place  for  24  hours, 
during  which  the  water  and  silt!1  will  settle  to  the 
bottom.  Their  percentage  by  volume  can  then  be 
correctly  read  on  the  burette  divisions,  and  the  per- 
centage by  weight  calculated  from  the  specific  grav- 
ities. 

Details  Involved  in  Determination  of  Distillation. 
Since  the  method  of  determination  by  distillation  is 


MOISTURE  CONTENT 


187 


STILL   WITH    HOOD    USED    FOR    WATER    DETERMINATION 

Many  methods  are  utilized  in  determining  the  water  content  of  oil. 
The  simplest  and  most  accurate  method  for  fuel  oil  tests  is  that 
of  distillation.  In  this  method  a  sample  of  the  oil  is  poured  into 
a  still  and  raised  sufficiently  in  temperature  to  evaporate  the 
water  and  not  the  ingredients  of  the  oil.  By  condensing  the  mois- 
ture and  ascertaining  its  proportions  the  moisture  content  is 
easily  ascertained. 


to  be  recommended  above  all  others,  we  shall  now 
proceed  to  the  details  of  its  accomplishment.  Stated 
in  simple  words,  the  method  consists  in  heating  a 
sample  slightly  above  the  boiling  point  of  water  but 
not  so  high  as  to  cause  the  vaporizing  of  other  in- 
gredients of  the  oil.  As  a  consequence,  the  water 
passes  over  and  leaves  water-free  oil  in  the  sample. 


188  FUEL  OIL  AND  STEAM  ENGINEERING 

The  Apparatus  Involved  and  Preliminary  Pro-) 
ceedings.— To  quantitatively  determine  the  moisture 
content  the  sample  is  placed  in  a  copper  vessel  known 
as  a  still,  which  is  about  4  in.  in  diameter  and  6  in. 
high.  The  still  is  then  placed  in  an  asbestos  hood 
through  which  a  projecting  stem  connects  to  a  con- 
denser and  a  burette  where  the  condensate  is  meas- 
ured in  a  graduated  tube.  The  (can  from  which  the 
sample  is  to  be  drawn  lis  first  immersed  in  a  water 
bath  with  its  cover  released.  After  the  water  consti- 
tuting the  bath  has  been  raised  to  a  temperature  of 
150°  to  170°  F.,  the  cover  to  the  can  is  fastened 
tightly,  and  the  can  agitated  for  several  minutes  in 
order  that  any  water  that  may  have  settled  at  the 
bottom  may  be  thoroughly  mixed  with  the  oil.  For 
successful  agitation  the  sample  can  should  not  be 
filled  more  than  two-thirds  with  oil.  '  100  cc.  of  oil 
sample,)  measured  in  a  graduated  jar,  are  now  poured 
into  the  still.  The  exact  measurement  of  the  oil  is 
difficult  without  experience,  as  froth  collects  on  the 
surface  of  the  oil  and  tends  to  obscure  any  definite 
meniscus. 

The(  jar  is  next  washed  with  50  cc.  of  benzol  and 
50  cc.  of  toluene.  The  washings  are  poured  into  the 
still.  :  Since  toluene-  has  a  tendency  to  absorb  small 
quantities  of  water,  accurate  results  may  be  inter- 
fered with  if  the  toluene  is  not  previously  saturated. 
In  order  to  avoid  such  a  possibility  when  opening  a 
fresh  bottle,  5  to  10  cc.  of  water  should  be  added.  The 
presence  of  water  in  the  bottom  of  the  bottle  shows 
that  the  toluene  is  saturated,  but  care  must  be  taken 
not  to  pour  this  water  into  the  still  wrhen  washing 
with  the  toluene. 

The  still  must  be  gently  shaken  without  splash- 
ing in  order  that  its  contents  may  be  well  mixed,  and 
then  placed  in  the  asbestos  hood  and  connected  with 
the  condenser.  A  hood  and  cover  are  provided,  as 
shown  in  the  illustration,  to  surround  the  still  with  a 
blanket  of  air-  at  a  uniform  temperature.  The  still  is 
then  heated  gradually  to  a  temperature  of  about  300° 
F.,  which  is  uusally  accomplished  after  about  fifteen 


MOISTURE  CONTENT  189 

minutes  of  heating.  Since  the  boiling  point  of  water 
has  been  now  exceeded,  the  moisture  in  the  sample 
begins  to  pass  over  into  the  condenser,  and  after  the 
lapse  of  another:  fifteen  minute  period  the  distillation 
is  complete.  A  thermometer  for  temperature  control 
is  seen  at  the  right  side  of  the  asbestos  hood  in  the 
illustration. 

The  Process  of  Distillation.— The  process  of  dis- 
tillation is  interesting.  At  about  176.7°  F./theibenzol 
first  passes  over.  This  wets  the  condenser  tube  so 
that  the  moisture  which  is  soon  to  follow  will  not 
readily  cling  to  the  tube  but  the  more  easily  pass  down 
into  the  measuring  burette.  The  toluene  'follows  at 
230.5°  F.,  and  carries  down  with  it  any  water  which 
happens  to  remain  in  the  condenser  tube.  The  tolu- 
ene does  not,  however,  pass  over  in  its  entirety,  since 
usually  from  15  to  20  cc.  remain  in  the  still  with  the 
oil.  In  order  to  make  up  this  deficiency  in  ftoluene 
(about  15  cc.  are  poured  down  the  condenser  tube  to 
free  any  small  drops  of  wrater  J  that  may  persist  in 
remaining.-  j  This,  however,  does  not  affect  the  accu- 
racy of  the  work,  since  the  water  content  is  finally 
separated  by  filtration  and  the  wTater  content  thus 
obtained  is  alone  measured. 

The  still  while  at  a  high  temperature  is  drained, 
and,  as  its  contents  are  now  entirely  free  from 
water,  it  may  be  used  again  without  additional 
cleaning. 

Anylsmall  drops  of  waterjthat  cling  to  the  side  of 
the  graduated  measuring  tubes  must  be  released  by  a 
short  wire./  If  now  the  resultant  water  is  read  in  cc. 
the  percentage  of  water  by  volume  in  the  oil  is  easily 
obtained,  since  the  water  is  separated  from  the 
mixture  of  benzol  and  toluene  in  the  filter  bottle. 

A  Numerical  Determination. — Let  us  then  follow 
this  process  by  means  of  an  illustrative  example.  Let 
us  assume  that  100  cc.  of  oil  have  been  drawn  as  a 
sample,  that  100  cc.  of  benzol  and  toluene  have  been 
poured  with  it  into  the  still,  and  that  the  resultant 
distillate  shows  .484  cc.  of  water.  It  then  follows 


190  FUEL  OIL  AND  STEAM  ENGINEERING 

directly  that  the  percentage   of  water  by  volume  is 
.484. 

Error  in  Assuming  Percentage  by  Weight  is 
Same  as  Percentage  by  Volume. — The  percentage  of 
water  by  weight  is  not  exactly  equal  to  its  percentage 
by  volume,  but  may  be  taken  equal  to  it  for  all  prac- 
tical purposes  of  boiler  testing.  This  error  is  then 
nominal  except  with  very  light  oils  or  any  oil  with 
considerable  moisture  content.  Thus,  if  an  oil  sample 
of  100  cc.  contains  .50  cc.  of  water  at  60°  F.,  it  will 
weigh  .484  X  -999  =  .483 5  grm. 

The  percentage  of  water  by  weight  is  therefore 
.4835  divided  by  .9673,  which  equals  .50%.  The  factor, 
.9673,  appearing  in  the  above,  is  the  specific  gravity  of 
the  oil  sample  at  60°  F.  This  was  ascertained  by 
means  of  a  Westphal  balance,  which  is  shown  in  detail 
in  the  preceding  chapter. 


CHAPTER  XXIII 

DETERMINATION  OF  HEATING  VALUE 
OF  OILS 


To  determine  the  efficiency  of  boiler  operation  it 
is  necessary  to  know  the  heat  producing  value  of  the 
oil  used  in  firing.  Again,  since  oil  is  usually  sold  com- 
mercially by  the  barrel,  the  heat  producing  value  of 
the  product  must  be  known  in  order  that  the  engineer 


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19300  J3500 


THE  GRAPHIC  LAW  FOR  CALORIFIC  VALUE  OF  FUELS 

In  this  illustration  is  shown  how  a  large  number  of  experimental 
values  often  enable  the  engineer  to  ascertain  an  empirical  law  for 
setting  forth  experimental  data.  By  plotting  the  heat  determina- 
tions for  fuel  oil  against  their  gravity  expressed  in  Baume  read- 
ings, the  experimenter  deduced  an  equation  for  determining  the 
calorific  value  of  water  free  oil  when  its  gravity  Baume  is  known. 

191 


192  FUEL  OIL  AND  STEAM  ENGINEERING 

may  ascertain  the  economic  value  the  product  may 
prove  to  his  client  in  its  use  in  the  power  plant 
for  the  generation  of  steam. 

An  Approximate  Method  Based  on  the  Baume 
Scale. — The  heat  producing  value  of  oil  is  usually  ex- 
pressed in  the  number  of  heat  units  per  unit  of  mass 
that  the  oil  will  give  out  when  it  is  completely  burned 
in  a  furnace.  In  engineering  practice  this  is  usually 
expressed  in  B.t.u.  per  pound  of  oil  so  burned. 

There  are  various  methods  of  ascertaining  this 
value.  An  approximate  method  is  that  based  upon 
the  gravity  of  the  oil.  To  establish  this  method  a 
large  number  of  samples  with  the  gravities  of  the 
oil  free  from  moisture  expressed  in  Baume  read- 
ings were  accurately  determined  as  to  their  heating 
value.  These  values  were  plotted  on  a  chart  and  it 
was  found  that  the  following  relationship  is  approxi- 
mately true  in  which  H  represents  the  heat  units  in 
B.t.u.  liberated  per  pound  of  fuel  burned: 

H  =  17680  +  60  B (1) 

Thus  in  analyzing  a  composite  sample  of  forty 
samples  of  Kern  River  oil,  the  United  States  Bureau 
of  Mines  found  that  its  calorific  value  was  18562  B.t.u. 
per  Ib.  of  oil,  in  which  the  oil  had  .5%  moisture,  and 
that  the  Baume  reading  of  this  oil  when  free  from 
water  was  14.78°.  According  to  the  formula  above, 
which  was  first  announced  by  Professor  Joseph  N. 
LeConte  of  the  University  of  California,  the  heating 
value  of  this  oil  when  free  from  moisture  should  be 

H  =  17680  +  60  X  14.78  =  18,566  B.t.u.  per  Ib. 

In  this  instance  then  it  is  seen  that  this  approximate 
method  checks  with  considerable  accuracy,  since  the 
water-free  oil  showed  by  actual  test  to  have  a  heating 
value  of  18,658  B.t.u.  per  Ib.  In  the  utilization  of  this 
formula,  however,  it  must  be  remembered  that  the  oil 
must  be  taken  as  anhydrous,  or  in  other  words  that  the 
oil  sample  is  moisture  free. 

Dulong's  Formula  Based  on  the  Ultimate  Analy- 
sis.— The  second  method  of  arriving  at  the  calorific 
value  of  crude  petroleum  is  by  means  of  Dulong's 


HEATING  VALUE  193 

formula.  This  formula  is  based  upon  the  ultimate 
analysis  of  the  oil  in  which  the  heat  value  of  carbon, 
hydrogen,  and  sulphur  are  taken  into  account. 

In  the  burning  with  oxygen  of  one  pound  of  car- 
bon, one  pound  of  hydrogen,  and  one  pound  of  sul- 
phur it  has  been  established  experimentally  that  14600, 
62000,  and  4000  B.t.u.  of  heat  energy  are  respectively 
given  out.  Hence  it  is  evident  that  if  a  one-pound 
sample  of  fuel  oil  has  C  proportions  by  weight  of  car- 
bon, H  proportions  of  weight  of  hydrogen  and  S  pro- 
portions by  weight  of  sulphur,  the  total  heat  given 
out  by  the  one-pound  sample  will  be 

H  =  14,600  C  +  62,000  H  +  4000  S 

In  the  chemical  analysis  of  fuels  a  certain  amount 
of  oxygen  (O)  is  always  encountered.  This  of  course 
kills,  as  it  were,  its  combining  weight  of  hydrogen. 
Since  oxygen  unites  with  one-eighth  of  its  weight  of 
hydrogen,  the  net  hydrogen  available  for  heat  gen- 

O 

crating  purpose  is  (H ). 

8 

Hence  we  have  Dulong's  formula 

O 

H  =  14,600  C  +  62,000  (H )  +  4000  S. . . .  (2) 

8 

For  California  oils,  Dulong's  formula  seems  to 
indicate  a  heat  value  per  pound  of  about  5%  i  '  excess 
of  the  true  value.  In  other  words,  it  indicates  a  heat- 
ing value  of  about  19,500  B.t.u.  per  Ib.  of  California 
crude  oil,  while  a  great  number  of  calorific  tests  have 
shown  that  the  average  value  is  about  18,500  B.t.u. 
per  Ib. 

The  Fuel  Calorimeter.  —  The  most  accurate 
method  of  determining  the  heating  value  of  a  sample 
of  oil  is  by  the  employment  of  some  form  of  calori- 
meter, wherein  a  sample  of  definite  mass  is  burned 
and  the  heat  given  out  ascertained.  The  fuel  calori- 
meter is  an  entirely  different  instrument  from  the 


194  FUEL  OIL  AND  STEAM  ENGINEERING 


THE     EMERSON     FUEL    CALORIMETER 

In  this  type  of  calorimeter  the  fuel  sample  is  placed  in  the  bomb, 
the  bomb  inverted,  as  shown  in  the  sketch,  and  filled  with  oxygen 
which  is  accomplished  by  means  of  the  spindle  valve  at  the  top 
of  the  bomb.  After  filling  the  calorimeter  with  distilled  water  and 
firing  the  sample  by  means  of  an  electric  circuit,  the  rise  in  tem- 
perature of  the  water  in  the  calorimeter  is  ascertained,  and  the 
calorific  value  of  the  fuel  thus  determined. 


THE    ATWATER-MAHLER    BOMB    CALORIMETER 

This  type  of  calorimeter  is  applicable  to  the  highest  scientific  work. 
It  permits  of  determining  the  exact  amount  of  water  and  carbon 
dioxide  in  the  products  of  combustion,  thus  enabling  the  error  due 
to  the  condensation  of  the  water  in  the  bomb  to  be  overcome  and 
therefore  making  it  possible  to  calculate  the  exact  amount  of  heat 
the  fuel  should  produce  under  boiler  conditions. 


HEATING  VALUE  195 

steam  calorimeter  used  for  measuring  the  moisture  of 
steam,  which  was  described  in  an  earlier  chapter.  The 
fuel  calorimeter  is  a  true  instrument  for  measuring 
heat,  as  its  name  implies.  Calorimeters  in  general 
may  be  divided  into  two  classes,  the  one  known  as  the 


.  THE  PARR  CALORIMETER  UNASSEMBLED 
In  this  type  of  calorimeter  a  carefully  weighed  oil  sample  is  burned 
with  a  chemical  agent  without  the  use  of  free  oxygen.  The  ease 
with  which  it  may  be  manipulated  commends  its  use  for  commer- 
cial application.  For  scientific  work,  however,  a  type  of  the 
Bomb  calorimeter  is  to  be  preferred. 

continuous  method  and  the  other  as  the  discontinuous 
method.  In  the  former  instance  a  sample  is  contin- 
ually burned,  and  the  average  results  ascertained  over 
a  considerable  period.  This  method  is  only  applicable 
for  gases  and  some  unusual  types  of  oils.  The  discon- 
tinuous process  is  on  the  other  hand  the  most  advan- 
tageous for  the  determination  of  the  heating  value  of 
crude  petroleum. 

Several  methods  are  employed  in  the  application 
of  the  discontinuous  calorimeter.  Most  forms  of  such 
calorimeters  consist  essentially  of  a  strong  combustion 
chamber  with  a  crucible  for  holding  the  sample ;  valves 
for  charging  the  chamber  with  oxygen  in  order  to 
properly  burn  the  sample ;  a  method  of  igniting  the 
sample;  and  a  vessel  of  water  in  which  the  bomb  or 


196 


FUEL  OIL  AND  STEAM  ENGINEERING 


explosion  chamber  is  immersed  in  order  that  the  re- 
sultant heat  may  be  absorbed  by  this  water  and  thus 
carefully  measured.  This  latter  vessel  is  usually  sit- 
uated in  a  second  compartment  which  serves  as  a 
jacket.  The  main  principle  upon  which  such  calori- 
meters depend  is  based  upon  the  fact  that  the  burning 
of  carbon,  hydrogen,  and  sulphur  with  an  artificial 
supply  of  oxygen  presents  the  most  accurate  method 
of  liberating  the  latent  heat  in  the  fuel  and  the  ascer- 
taining of  its  quantitative  proportions.  Types  of  this 
calorimeter  familiar  in  the  market  are  known  as  the 
Mahler,  the  Hempel,  the  Atwater,  the  Emerson,  and 
the  Carpenter. 

s  The  Parr  Calorimeter. — In  the  commercial  deter- 
mination of  the  heating  value  of  crude  petroleum, 
however,  it  is  often  incon- 
venient to  secure  oxygen 
under  the  proper  pressure 
required  for  the  successful 
operation  of  this  type  of 
calorimeter.  In  recent  years 
there  has  appeared  upon 
the  market  a  much  simpler 
design  of  calorimeter 
which  seems  to  have  suffi- 
cient accuracy  for  most 
commercial  uses  and  is  in- 
deed quite  simple  in  opera- 
tion. This  is  known  as  the 
Parr  calorimeter  and  is  the 
invention  of  Professor 
S.  W.  Parr  of  the  Univer- 
sity of  Illinois. 

The  Principle  of  Opera- 
tion.— In  the  Parr  calori- 
meter a  definite  mass  of  oil 
is  introduced  into  a  strong 
cylinder  of  metal  called  the  cartridge,  along  with  some 
accelerator  together  with  a  measure  of  potassium 
peroxide.  The  potassium  peroxide  furnishes  oxygen 
for  combustion  and  the  accelerator,  which  is  usually 


CROSS-SECTIONAL    VIEW 
OF  THE  PARR  CALOR- 
IMETER 


HEATING  VALUE 


197 


potassium  chloride,  insures  that  all  the  fuel  may  be 
burned.  The  ignition  is  effected  electrically  by  the 
burning  out  of  a  fine  iron  wire  immersed  in  the  mix- 
ture. 

As  shown  in  the  illustration,  the  cartridge  D,  in 
which  the  sample  is  placed,  is  closed  up,  inserted  into 
a  can  of  water  A,  and  the  whole  place.d  in  a  fibre  ves- 


THE    MAHLER    BOMB    CALORIMETER 

This  type  of  calorimeter  represents  one  of  the  most  accurate  for 
the  determination  of  the  calorific  value  of  fuel  oil.  The  bomb  is  of 
enameled  steel.  The  burning  of  the  oil  sample  is  accomplished  by 
supplying  an  outside  source  of  oxygen  as  in  the  Emerson  Calori- 
meter. 

sel  B,  which  thus  brings  about  careful  heat  insulation. 
After  causing  an  explosion  by  means  of  an  electrical 
contact  spark  in  the  cartridge  D,  the  cartridge  is  given 
a  rotary  motion  by  means  of  the  pulley  P  and  the 
heat  which  is  given  out  from  the  cartridge  due  to  the 
burning  of  the  ingredients  is  rapidly  absorbed  by  the 
water  in  the  vessel  A.  If  then  we  know  the  mass  of 
the  sample  burned,  and  the  mass  and  temperature  of 
the  water  before  and  after  the  explosion,  we  can  com- 
pute the  heat  value  of  the  fuel. 

Detailed    Operation  of    the  Parr  Calorimeter. — 

Let  us  now  go  into  the  details  of  this  calorimeter 
operation.  A  well  lighted  closet  should  be  used  for 
all  calorimeter  work  so  that  air  currents  which  might 
otherwise  prevent  uniform  radiation  can  thus  be  elim- 
inated. The  outside  of  the  calorimeter  cup  and  of  the 


198  FUEL  OIL  AND  STEAM  ENGINEERING 

fibre  insulating  case  should  be  entirely  free  from 
moisture  for  the  same  reason.  The  calorimeter  cup  A 
is  filled  with  2000  grams  of  water.  The  cartridge  or 
bomb  in  which  the  sample  is  placed  has  a  water  equiv- 
alent of  135  grams ;  that  is,  it  absorbs  the  same  amount 
of  heat  as  135  grams  of  water  would  under  the  same 
range  of  temperature.  Hence,  the  total  water  equiva- 
lent We  is  2135  grams.  As  the  mass  of  oil  is  also  deter- 
mined in  grams,  the  water  equivalent  We  divided  by 
the  mass  of  oil  fired,  W0,  becomes  an  abstract  ratio, 
and,  if  this  ratio  is  multiplied  by  the  rise  in  tempera- 
ture of  the  water  in  degrees  Fahrenheit,  the  result  is 
heat  units  per  pound  of  oil,  or,  if  the  temperature  is 
expressed  in  degrees  Centigrade,  the  result  becomes 
calories  per  gram. 

The  water  is  best  measured  in  a  2000  cc.  flash. 
About  2003  cc.  of  water  are  used  instead  of  an  exact 
2000  cc.,  since  the  specific  gravity  of  water  at  ordinary 
room  temperatures  is  slightly  less  than  unity  and  this 
increased  volume  is  necessary  to  measure  weights  vol- 
umetrically. 

The  thermometer  which  is  employed  in  tempera- 
ture measurements  has  a  range  of  from  65° F.  to  90° F. 
and  is  standardized  by  the  Bureau  of  Standards  at 
Washington.  Graduation  errors  are  known  to  within 
.01°F.  The  thermometer  scale  is  divided  to  .05°  and 
with  care  may  be  read  to  .005°.  The  greatest  chance 
for  error  in  fuel  calorimeters  is  in  reading  tempera- 
tures, since  it  is  difficult  to  avoid  parallax.  Conse- 
quently as  the  rise  in  temperature  seldom  exceeds  5°, 
an  error  of  .01°  is  equivalent  to  2%  error  in  the  work. 

Preliminary  Precautions.  —  Before  placing  the 
sample,  the  cartridge  should  be  wiped  clean  and  dry, 
as  moisture  will  condense  on  it  if  it  has  been  standing 
for  some  time.-  The  top  and  bottom  pieces,  as  well  as 
the  gaskets  and  electrical  terminals,  should  be  dry, 
since  the  moisture  on  them  takes  part  in  the  chemical 
reaction  and  thus  introduces  considerable  error.  The 
cartridge  should  be  tightly  assembled,  and  1.500  grams 
of  accelerator  (potassium  chloride),  weighed  to  the 
nearest  reading  of  .005  grams,  placed  therein.  The 


HEATING  VALUE  199 

oil  is  weighed  in  a  small  flask  with  an  eye  dropper  and 
about  .04  to  .05  grams  (8  to  12  drops)  dropped  into 
the  cartridge  upon  the  accelerator  which  absorbs  the 
oil.  Upon  reweighing  the  flask  of  oil  and  the  dropper, 
the  net  weight  of  the  oil  sample  is  at  once  obtained. 
A  measure  full  of  sodium  peroxide  is  added  and  the 
contents  thoroughly  mixed  with  a  stiff  wire.  With 
care  no  oil  and  very  little  peroxide  will  adhere  to  the 
wire.  The  sodium  peroxide  should  be  supplied  by  the 
calorimeter  manufacturer,  as  inferior  grades  are  apt 
to  contain  variable  and  detrimental  products  of  com- 
bustion. 

About  3  in.  of  No.  4  iron  wire  for  firing  the  charge 
are  next  looped  on  the  firing  terminals  and  tested  out 
to  insure  a  good  electrical  contact.  The  firing  current 
is  usually  supplied  by  a  few  dry  cells  or  from  a  storage 
battery. 

The  stem  of  the  bomb  is  next  fastened  in  place 
and  the  vanes  attached.  The  cartridge  is  placed  in  the 
calorimeter  cup,  the  cover  and  pulley  attached,  and 
the  cartridge  stirred  by  a  small  motor  for  about  five 
minutes.  The  motor  may  be  of  the  toy  variety  and  is 
usually  placed  in  the  lighting  circuit  with  a  lamp 
resistance.  The  electric  circuit  is  controlled  with  a 
two-throw  switch  so  that  the  motor  may  be  cut  in  and 
out  without  interfering  with  the  illumination  in  the 
closet.  The  motor  speed  should  be  as  nearly  constant 
as  possible,  since  a  variable  speed  will  cause  a  variable 
rate  of  radiation  from  the  calorimeter.  The  rotating 
bomb  should  have  from  100  to  150  revolutions  per 
minute. 

The  Explosion  of  the  Charge  and  the  Taking  of 
Temperatures. — The  thermometer  is  next  placed  into 
the  water  bath  through  a  hole  in  the  cover  and  should 
be  supported  so  that  it  does  not  touch  the  metal  cup 
which  contains  the  water.  After  a  steady  initial  tem- 
perature has  been  reached,  the  firing  circuit  is  com- 
pleted through  the  pulley,  and  the  resulting  tempera- 
tures read  every  minute  for  the  succeeding  ten  min- 
utes, in  order  to  ascertain  the  correction  to  be  made 
for  uniform  radiation.  This  series  of  readings  is  taken 


200  FUEL  OIL  AND  STEAM  ENGINEERING 

in  order  to  ascertain  the  law  of  radiation  and  then  to 
make  a  proper  correction  for  the  error  involved. 

Thus,  for  a  period  of  about  five  minutes  the  tem- 
perature will  rise  until  a  maximum  is  reached,  after 
which  it  will  begin  to  fall.  The  radiation  during  the 
first  five  minutes  is  assumed  to  be  at  the  same  rate 
as  that  observed  during  the  entire  radiation  period. 

Let  us  assume  the  following  experimental  data: 

Water  equivalent  of  calorimeter 135     grams 

Weight   of   water  used 2000 

Weight   of   oil    used 3765 

Per  cent  moisture   in   oil 5% 

Weight    of    accelerator 1500 

Room   temperature    70°  F. 

Temperature  of  mixture  when  fired,  73.665°  F. 

Com'-ustion    Period 

1  min 77.45 

2  "       78.15 

3  "       78.42 

4  "       78.44 

5  "       78.45 

Radiation   Period 

6  min    78.44 

7  "  78.42 

8  "  78.40 

9  "  78.385 

10  "  78.370 

The  Correction  for  Temperature  Readings. — Since 
from  the  above  it  is  seen  that  the  temperature  falls 
off  from  its  highest  reading,  th,  or  78.45°F.  to  78.37°F. 
in  five  minutes,  it  is  evident  that  in  one  minute  it 
would  fall  off  .016° F.  As  a  consequence  at  the  end  of 
the  combustion  period,  in  reality  the  thermometer 
should  have  read  greater  than  th  or  78.45°F.  by  an 
amount  equal  to  the  radiation  tr  which  is  (.080)  over 
the  first  five  minute  period.  In  addition  to  this  cor- 
rection, by  consulting  a  correction  scale  furnished  by 
the  Bureau  of  Standards,  the  thermometer  should  be 
corrected  for  78.45°F.  by  an  amount  equal  to  tc  or 

2 

(-.053°)  and  for  the  minimum  temperature  tm  or 
73.665°F.  equal  to  tc  or  (-.043°).  From  the  instru- 
ment maker  there  has  also  been  furnished  data  indi- 
cating a  correction  for  the  chemicals  and  wire  em- 
ployed, amounting  to  tw  or  (—0.373).  Hence  the  true 


HEATING  VALUE  201 

maximum  temperature  t2  and  the  true  minimum  tem- 
perature t-L  are  ascertained  by  the  formulas : 


t       th    4-    t,.    4-    tr    4-    tw 

.   (3) 

2 

tn    tm  4-   tc       • 

.  (4) 

1 

Substituting  in  the  particular  case  cited,  we  have 

t2  =  78.450  —  .053  +  .080  —  .373  =  78.104 
^  =  73.665  —  .043  =  73.622 

Since  a  careful  comparison  of  this  calorimeter 
with  the  most  accurate  type  of  calorimeter  known  in 
the  laboratory  has  shown  that  the  heating  value  per 
pound  of  oil  is  .73  of  the  total  heat  liberated,  we  have 

.73  We 

(t»—  O   ....................  (5) 


W0 
We  now  have  in  this  instance 

.73X2135  (78.104  —  73.622) 
H=-  -=  18562  B.tu. 

.3765  per  Ib.  of  oil 

as  fired. 

If  it  is  desired  to  ascertain  the  heating  value  of 
this  oil  when  free  from  moisture,  it  is  only  necessary 
to  divide  by  the  percentage  of  dry  oil  in  the  fuel.  Thus 
if  the  oil  sample  contained  .50%  of  moisture  we  find 
that  the  heating  value  per  pound  of  dry  oil  would  be 
according  to  this  calorimeter  determination  18562 
divided  by  .995  which  is  18658  B.t.u. 

Higher  and  Lower  Heating  Value.  —  In  the  opera- 
tion of  the  calorimeter  the  gases  produced  by  the 
combustion  of  the  sample  of  oil  are  cooled  down  to  the 
temperature  of  the  water  in  the  calorimeter.  In  the 
case  of  carbon  which,  on  igniting  with  oxygen  pro- 
duces CO2,  this  cooling  of  the  gas  has  no  important 


202  FUEL  OIL  AND  STEAM  ENGINEERING 

effect  since  CO2  remains  a  gas  at  all  ordinary  tempera- 
tures. Hydrogen,  on  the  other  hand,  on  uniting  with 
oxygen  forms  steam,  H2O,  which  is  condensed  to 
water  in  the  calorimeter  as  soon  as  its  temperature 
drops  below  212°F.,  and  in  condensing  gives  up  its 
latent  heat  to  the  calorimeter.  When  fuel  oil  is  burned 
under  a  boiler  the  gases  are  always  discharged  at  a 
temperature  higher  than  212°  so  that  the  latent  heat 
of  steam  formed  by  the  combustion  of  the  hydrogen 
content  is  not  available  and  cannot  be  absorbed  by 
the  boiler.  Hydrogen  combines  with  eight  times  its 
weight  of  oxygen  so  that  for  each  pound  of  hydrogen 
burned  nine  pounds  of  water  are  formed,  and  as  the 
latent  heat  of  steam  is  970  B.t.u.  per  pound,  there  are 
approximately  9X^70  =  8730  B.t.u.,  which  cannot  be 
recovered  unless  the  gases  are  cooled  below  212°F. 
Deducting  this  from  62000  B.t.u.,  the  heating  value  of 
one  pound  of  hydrogen  determined  by  a  calorimeter, 
gives  52,270  B.t.u.,  which  is  called  the  lower  heating 
value  of  hydrogen. 

Since  oil  contains  a  considerable  proportion  of 
hydrogen  it  has  a  lower  heating  value  as  well  as  the 
ordinary  or  higher  heating  value.  If  a  sample  of  oil 
contains  12  per  cent  of  hydrogen,  and  the  higher  heat- 
ing value  by  calorimeter  test  is  18562  B.t.u.  per  pound, 
then  the  lower  heating  value  is  18562  —  .12  X  8730  = 
17515  B.t.u.  per  pound.  In  boiler  testing  work  it  is 
the  universal  custom  to  base  calculations  on  the  higher 
heating  value  as  given  by  the  calorimeter,  but  the 
lower  heating  value  is  ordinarily  used  when  calculat- 
ing the  efficiencies  of  gas  engines. 


CHAPTER   XXIV 

CHIMNEY  GAS  ANALYSIS 

We  have  found  in  preceding  discussions  that  for 
practical   purposes  the   gases  passing  out  through   a 

chimney  from  the  central 
station  boiler  are  usually  con- 
sidered to  be  composed  of 
carbon  dioxide,  oxygen,  car- 
bon monoxide  and  nitrogen. 
Since  these  constituents  are 
usually  determined  volumet- 
rically  we  sh  a  1 1  represent 
them  by  the  symbols  V±,  V2, 
V3,  and  V4,  respectively.  We 
shall  now  proceed  to  a  discus- 
sion of  the  usual  methods  em- 
ployed in  determining  the  flue 
gas  analysis  during  the  boiler 
test. 

The  Taking  of  the  Flue  Gas 
Samples  and  Analysis — Cer- 
tain solutions  have  been 
found  in  the  chemist's  labora- 
tory that  will  absorb  carbon 
dioxide  and  will  not  absorb 
oxygen,  carbon  monoxide  or 
nitrogen.  Again  another  so- 
lution has  been  found  that 
will  absorb  oxygen  but  will 
not  absorb  carbon  monoxide 
or  nitrogen.  And  still  a  third 
solution  has  been  found  that 
will  absorb  carbon  monoxide 
but  will  not  absorb  nitrogen. 
A  carbon  dioxide  recorder  If  then  a  contrivance  can  be 


203 


204  FUEL  OIL  AND  STEAM  ENGINEERING 

set  up  so  that  a  flue  gas  sample  may  be  successively 
washed  in  these  solutions,  a  means  is  provided  for 
determining  an  analysis  by  volume. 

Let  us  then  see  how  the  flue  gas  analysis  is  taken. 
The  apparatus  (see  page  210)  consists  of  a  wooden 
case  with  removable  sliding  doors  which  contain  a 
measuring  tube  or  burette  B,  three  absorbing  bottles 
or  pipettes,  P',  P",  and  P"'.  In  addition  a  leveling 
bottle  A  and  connecting  tube  T  are  also  provided. 

The  tube  E  is  connected  to  the  point  in  the  chim- 
ney situated  immediately  beyond  the  breeching.  The 
instrument  is  first  set  in  operation  by  closing  the  stop- 
cocks f,  g,  and  e,  d  being  open.  By  lowering  the  level- 
ing bottle  A,  a  sample  of  the  gas  is  drawn  into  the 
burette  B.  This  preliminary  sample  is  then  expelled 
to  the  atmosphere  by  raising  the  bottle  A  and  allowing 
the  gas  thus  put  under  pressure  to  pass  out  through 
a  by-pass  at  d.  This  process  is  continued  until  it  is 
considered  that  an  average  sample  has  been  drawn 
into  the  burette  B.  The  leveling  bottle  A  is  next 
lowered  so  as  to  cause  the  water  in  burette  B  to  come 
to  its  zero  mark.  By  raising  the  bottle  A  the  water  is 
again  forced  into  burrette  B  and  the  gas  sample  ex- 
pelled through  stopcock  e  into  the  pipette  P',  in  which 
there  is  a  chemical  solution  that  absorbs  carbon  diox- 
ide, but  will  not  absorb  oxygen,  carbon  monoxide  or 
nitrogen. 

To  Ascertain  the  Carbon  Dioxide  Content  of  a 
Flue  Gas.  —  Exactly  100  cc.  of  gas  were  originally 
drawn  into  the  burette  B.  If  now  the  leveling  bottle 
A  is  again  lowered  to  draw  the  gas  back  through  stop- 
cock e,  the  volume  in  the  burette  will  be  found  to 
have  lessened  in  quantity  so  that  instead  of  reading 
zero  it  now  reads  N±  which  indicates  directly  the 
volume  of  carbon  dioxide  that  was  present  in  the  gas, 
for  evidently  this  volume  has  been  absorbed  in  the 
pipette  P'.  Hence,  we  have 

V^N, (1) 

To  Ascertain  the  Oxygen  Content  of  a  Flue  Gas. 
In  a  similar  manner  the  gas  sample  in  the  burette  B  is 
now  forced  through  pipette  P",  in  which  is  a  solution 


CHIMNEY  GAS  ANALYSIS 


205 


that  will  absorb  free  oxygen  in  the  sample  but  will 
not  absorb  carbon  monoxide  or  nitrogen.  By  means 
of  the  leveling  bottle  A,  the  sample  is  next  drawn  back 
into  the  burette  B  and  a  reading  N2  noted.  It  is  now 
evident  that  the  oxygen  content  of  the  flue  gas  may 
be  computed  from  the  formula 

V2  =  N2-Vt (2) 

To  Ascertain  the  Car- 
bon Monoxide  Content  of 
a  Flue  Gas.- — The  pipette 
P'"  similarly  contains  a 
solution  which  readily  ab- 
sorbs the  carbon  monox- 
ide present  in  the  gas,  but 
will  not  absorb  nitrogen. 
Hence  we  proceed  as  in 
the  two  former  instances 
and  return  the  gas  sample 
to  the  burette  which  now 
reads  N3.  Consequently 
the  carbon  monoxide 
which  was  present  in  the 
flue  gas  is  obtained  from  the  formula 

To  Ascertain  the  Nitrogen  Content  of  a  Flue  Gas. 

We  assume  that  all  of  the  gas  which  remains  in  the 
sample  is  nitrogen.  Consequently  the  nitrogen  con- 
tent is  obtained  from  the  formula 


THE     RECORDING 
GAGE 

A  revolving  dial 
record  is  con- 
stantly in  operation 
in  the  modern  cen- 
tral station  for  fuel 
oil  consumption  in 
order  to  ascertain 
the  carbon  dioxide 
component  of  the 
flue  gases.  This 
view  gives  the 
reader  a  concep- 
tion of  its  appear- 
ance as  installed 
in  the  power  sta- 
tion. 


V4=100-(V1+V2 


(4) 


An  Approximate  Check  on  the  Orsat  Analysis. — 

Air  is  found  by  weight  to  have  76.85%  hydrogen  and 
23.15%  oxygen.  By  volume  this  analysis  will  be  found 
to  be  79.09%>  nitrogen  and  20.91%  oxygen.  Since  1 
unit  by  volume  of  oxygen  forms  1  unit  by  volume  of 
carbon  dioxide  in  the  burning  of  pure  carbon  the  actual 
percentage  of  nitrogen  in  the  chimney  gases  is  not 
altered  but  should  remain  79.09%  if  perfect  combus- 
tion is  maintained. 

On  the  other  hand,  when  imperfect  combustion  is 
tinder  way,  or  in  other  words,    when    some    carbon 


206 


FUEL  OIL  AND  STEAM  ENGINEERING 


monoxide  is  being  formed,  1  unit  by  volume  of  oxy- 
gen forms  2  units  by  volume  of  carbon  monoxide. 
Hence  when  pure  carbon  is  the  fuel,  the  suni  of  the 
percentages  of  carbon  dioxide,  oxygen,  and  J/£  the 
carbon  monoxide  must  be  in  the  same  ratio  to  the 


TO  BOILER  ROOM  INDICATOR 


TO  RECORDING  GAUGE 


ABSORPTION  CHAMBER 


INDICATING 
COLUMN 


FILTER 


WATER         ESi  •    •    •     GAS  INLET 

JAR 

A  RECORDER  FOR  COMBUSTION  OPERATION 

From  the  discussion  in  the  text  it  may  be  inferred  that  a  knowl- 
edge of  the  carbon  dioxide  component  of  the  flue  gas  enables  us 
to  judge  concerning  the  combustion  taking  place  in  the  furnace. 
The  principle  involved  in  the  type  of  carbon  dioxide  recorder  as 
shown  is  that  a  change  of  volume  in  a  gas  produces  a  change  of 
pressure.  A  continuous  sample  of  the  flue  gas  enters  at  A  and 
in  passing  through  the  absorption  chamber  the  carbon  dioxide  is 
absorbed  and  consequently  a  reduction  in  pressure  takes  place.  By 
the  calibration  of  suitable  manometer  tubes  the  instrument  may  be 
made  to  read  the  carbon  dioxide  component  direct. 


CHIMNEY  GAS  ANALYSIS  207 

nitrogen  present  as  the  oxygen  in  the  air  is  to  the 
nitrogen  component,  namely  as  20.91  :  79.09.  This  is 
a  convenient  check  upon  a  flue  gas  analysis  in  the 
progress  of  the  experiment.  Thus  if  an  analysis  of 
chimney  gas  is  found  to  contain  by  volume  9.5%  car- 
bon dioxide,  10.2%  carbon  monoxide,  5.2%  oxygen, 
and  75.1%  nitrogen,  according  to  this  proportion,  we 
should  have 

10.2 

9.5_|_5.2_| .  75. i  =  20.91   :  79.09 

2 

Upon  investigation  this  will  be  found  to  be  approxi- 
mately true  and  well  within  the  limit  of  experimental 
accuracy. 

As  California  crude  oil  contains  usually  about 
11%  of  hydrogen,  the  ready  checking  above  indicated 
proves  of  no  avail  since  the  hydrogen  content  is  not 
taken  account  of  in  the  Orsat  or  flue  gas  analysis. 
As  the  relationship  serves,  however,  to  clinch  our 
ideas  of  volumetric  proportions  of  entering  air  and 
outgoing  flue  gases,  it  is  well  to  bear  it  in  mind. 

In  boilers  fired  by  coal  containing  little  hydrogen 
the  CO  does  not  usually  exceed  1  or  2%  and  the  sum 
of  the  Orsat  readings  CO2  +  O  -f-  CO  is  usually  be- 
tween 20  and  21%.  When  burning  oil,  on  the  other 
hand,  the  sum  of  these  readings  may  be  as  low  as  16 
or  17%  due  to  the  large  proportion  of  hydrogen  in  the 
fuel,  which  means  an  apparent  nitrogen  content  of 
83  or  84%.  The  reason  for  this  is  that  the  water 
vapor  formed  by  the  burning  of  hydrogen  condenses 
in  the  Orsat  apparatus  and  occupies  practically  no  vol- 
ume, but  the  oxygen  which  unites  with  the  hydrogen 
brings  with  it  the  same  proportion  of  nitrogen  as  does 
the  oxygen  that  unites  with  the  carbon.  Consequently 
the  Orsat  indicates  a  larger  proportion  of  nitrogen 
than  would  occur  if  the  fuel  were  pure  carbon. 

Chemical  Formulas  for  Preparing  the  Absorption 
Solutions. — The  bottle  A  and  the  measuring  tube  or 
burette  B  contained  pure  water  only,  while  the  first 
pipette  P'  in  which  carbon  dioxide  is  absorbed  con- 
tains sodium  hydrate  dissolved  in  three  times  its 


208  FUEL  OIL  AND  STEAM  ENGINEERING 

weight  of  water.  The  second  pipette  P"  in  which  oxy- 
gen is  absorbed  contains  Pyrogallic  acid  dissolved  in 
sodium  hydrate  in  the  proportion  of  five  grams  of  the 
acid  to  100  cc.  of  the  hydrate,  and  in  the  third  pipette 
wherein  carbon  monoxide  is  absorbed  cuprous  chloride 
is  contained.  These  chemicals  are  sold  by  most  of  the 
large  dealers. 

Another  series  of  formulas  which  work  equally 
well  and  in  many  cases  are  more  easily  prepared,  are 
the  following: 

To  absorb  the  carbon  dioxide,  potassium  hydrox- 
ide is  used,  and  is  made  by  diluting  500  grams  of  com- 
mercial potassium  hydroxide  in  one  quart  of  water. 
To  absorb  the  oxygen,  potassium-Pyrogallite  is  used 
wherein  five  grams  of  solid  acid  in  100  cc.  of  potas- 
sium hydroxide  above  mentioned  is  prepared.  When 
over  28%  of  oxygen  is  present,  it  is  necessary  to  use 
12  grams  of  commercial  potassium  hydroxide  to  100 
cc.  of  water.  To  absorb  the  carbon  monoxide,  cuprous 
chloride  is  used  which  is  prepared  by  covering  the 
bottom  of  a  quart  measure  with  cuprous  chloride 
(Cu  O)  to  a  depth  of  ^ths  of  an  inch.  The  measure 
is  then  filled  with  hydro-chloric  acid,  shaken  and 
allowed  to  stand  until  it  becomes  colorless.  The  cop- 
per wire  is  then  placed  in  the  solution  and  left  to 
stand  for  a  number  of  hours. 

The  Hemphel  Apparatus  for  Determining  the 
Hydrogen  Content. — It  is  seen  from  the  above  descrip- 
tion that  no  means  are  provided  to  ascertain  whether 
or  not  the  hydrogen  content  of  the  fuel  is  being  prop- 
erly consumed.  This  determination  can  only  be  made 
by  the  refined  laboratory  apparatus  of  the  chemist. 
The  authors  consider  that  such  a  test  is  beyond  the 
scope  of  this  work,  hence  the  description  of  the  Hemp- 
hel apparatus  and  its  operation  will  not  be  .undertaken 
in  these  pages.  Standard  works  on  this  subject  are, 
however,  available  in  all  chemical  engineering  libra- 
ries for  those  who  desire  to  go  into  this  subject. 
Except  for  refined  tests  covering  certain  particular 
problems  in  combustion  the  Orsat  analysis  of  flue 
gases  is  considered  sufficiently  accurate  for  power 


CHIMNEY  GAS  ANALYSIS  209 

plant  practice.  Indeed,  in  most  instances,  as  we  shall 
see,  the  determination  of  the  carbon  dioxide  compo- 
nent alone  gives  us  sufficient  information  for  ordinary 
operating  conditions. 

Conclusion  on  the  Orsat  Analysis. — By  care  and 
a  little  patience,  the  experimenter  will  find  that  the 
Orsat  analysis  as  above  set  forth  can  be  taken  easily 
and  quite  accurately,  and  thus  a  splendid  lot  of  data 
obtained  wherewith  steam  boiler  economy  and  opera- 
tion can  be  checked.  If  wrong  conditions  of  combus- 
tion are  found  to  prevail  the  proper  adjustments  can 
then  be  made  in  the  furnace  and  its  accessories. 

We  shall, next  proceed  to  formulate  some  equa- 
tions whereby  the  data  gained  from  the  flue  gas  analy- 
sis may  be  thrown  into  more  useful  analytical  form. 


CHAPTER   XXV 

ANALYSIS     BY    WEIGHT,    AND    AIR    THEO- 
RETICALLY REQUIRED  IN  FUEL  OIL 
FURNACE 


In  the  last  discussion  it  was  found  that  Orsat 
analyses  of  chimney  gases  are  always  made  volumet- 
rically.  In  computing  combustion  data  from  these 
analyses,  however,  it  is  often  necessary  to  have  the 


THE    ORSAT    APPARATUS 

The  Orsat  apparatus  is  a  portable  instrument  contained  in  a 
wooden  case  with  removable  sliding  door  front  and  back,  as  shown 
in  its  simplest  form  in  this  illustration,  taken  from  the  report  of 
the  Power  Test  Committee  of  the  American  Society  of  Mechanical 
Engineers.  It  consists  essentially  of  a  measuring-  tube  or  burette, 
three  absorbing-  bottles  or  pipettes,  and  a  leveling-  bottle,  together 
with  the  connecting  tubes  and  apparatus.  The  bottle  and  measur- 
ing tube  contain  pure  water;  the  first  pipette,  sodium  or  potassium 
hydrate  dissolved  in  three  times  its  weight  of  water;  the  second, 
pyrogallic  acid  dissolved  in  a  like  sodium  hydrate  solution  in  the 
proportion  of  5  grams  of  the  acid  to  100  cc.  of  the  hydrate;  and 
the  third,  cuprous  chloride.  These  chemicals  are  sold  by  most  of 
the  large  dealers.  Details  of  how  this  apparatus  is  used  to  deter- 
mine the  chimney  gas  analysis  were  set  forth  in  a  previous  dis- 
cussion. 

210 


AIR  REQUIRED  211 

proportions  or  percentages  by  weight  instead  of  by 
volume.  The  volumes  of  carbon  dioxide,  oxygen, 
carbon  monoxide,  and  nitrogen  which  constitute  the 
chimney  gas  analysis  of  a  sample  volume  by  means  of 
the  Orsat  apparatus  will  be  represented  by  V\,  V2,  V3, 
V4,  respectively  in  this  discussion.  Let  us  now  see 
how  we  may  transfer  this  relationship  so  that  propor- 
tions by  weight  of  M1?  M2,  M3  and  M4  pounds  may 
respectively  set  forth  the  constituents  of  a  flue  gas 
sample  of  weight  M  pounds.  Since  we  are  only  in 
search  of  proportions  by  weight — that  is  a  ratio  of 
M±  to  M,  M2  to  M  etc.,  it  is  evidently  not  necessary 
to  actually  knowr  the  quantitative  values  of  the  weights 
involved. 

Fundamental  Laws  Involved. — In  a  previous  dis- 
cussion we  found  (see  page  50)  that  all  perfect  gases 
follow  the  composite  law — namely,  that  at  any  partic- 
ular state  the  product  of  its  pressure  p  and  volume  V 
is  equal  to  the  product  of  its  weight  M  and  absolute 
temperature  T  multiplied  by  a  constant  R,  or  math- 
ematically expressed 


Hence,  we  may  at  once  write  the  respective  mathemat- 
ical relationships  for  the  carbon  dioxide,  oxygen,  car- 
bon monoxide,  and  nitrogen  of  the  flue  gas. 

It  is  to  be  remembered  that  in  the  case  under 
consideration  the  pressure  p  and  the  temperature  T 
have  the  same  value  for  each  component  in  the  flue 
gas;  consequently,  we  shall  not  put  any  individual 
subscript  for  the  pressure  p  and  temperature  T,  so  that 
we  may  write  these  individual  expressions  as  follows : 

pV, 

pV1  =  M1R1T     or  M1  =  - 


pV2 
=  M,R.,T     or  M,= 


R2T 


212  FUEL  OIL  AND  STEAM  ENGINEERING 

pV3 


pV3=:M3R3T  or  M3  = 


pV4 

or  M,  = 


R4T 
and  for  the  gas  as  a  whole,  we  have 

Pv 


or  M  = 


RT 


In  our  previous  discussion  on  the  elementary 
laws  of  gases,  it  was  also  found  mathematically  that 
the  constant  R  for  any  perfect  gas  is  obtained  by 
dividing  1544  by  the  molecular  weight  of  the  gas  in 
question  (see  page  49). 

From  any  book  on  elementary  chemistry  we  find 
the  molecular  weight  m  of  carbon  dioxide  (CO2)  is  44, 
that  of  oxygen  (O2)  is  32,  that  of  carbon  monoxide 
(CO)  is  28,  and  that  of  nitrogen  (N2)  is  28. 

Relationship  of  a  Component  Weight  to  the 
Whole.  —  Bearing  this  in  mind,  it  is  seen  from  the 

1544 

above  mathematical  relationships  that,  since  R  =  —  —  , 

m 
we  have 


p 

=  Km1V1     if   K  =  - 
1544T  1544T 


R,T         1544T 


AIR  REQUIRED  213 

pV4          ni4pV4 

M4  = — =  Km4V4 

R4T         1544T 

pV  mpV 

M  = = =  KmV 

RT         1544T 

M  =  Km±  Vx  +  Km2  V2  +  Km3  V3  +  Km4V4  = 
K(m1V1  +  m2V2  -\-  m3V3  -)-  m4V4) 

Let  Cs  =  n^Vj.  -\-  m2V2  +  m3V3  +  m4V4 

.'.     M  =  KCH 
Also  M±  = 


Hence  -  -  = (1) 

M  KCS  Cs 

A  Concrete  Rule  for  Conversions. — This  last  equa- 
tion now  gives  us  a  simple  and  ready  rule  for  deter- 
mining proportions  by  weight  if  the  proportions  by 
volume  are  given.  In  other  words,  this  rule  may  be 
stated  as  follows : 

In  any  analysis  by  volume,  the  analysis  by  weight 
is  found  by  first  summing  the  products  formed  by 
multiplying  each  component  volume  by  its  particular 
molecular  weight.  If  now  this  summation  Cs  is 
divided  into  the  product  of  a  component  volume  and 
its  particular  molecular  weight,  the  proportion  by 
weight  of  that  component  is  at  once  ascertained. 

An  Illustrative  Example. — Thus,  a  flue  gas  analy- 
sis shows  the  following  proportions  by  volume :  carbon 
dioxide  (CO2)  .086;  oxygen  (O2)  .110;  carbon  monox- 
ide .011 ;  and  nitrogen  (N2)  .793%.  Let  us  determine 
the  proportions  by  weight  present  in  this  particular 
flue  gas. 

Since  the  molecular  weights  of  carbon  dioxide, 
oxygen,  carbon  monoxide  and  nitrogen  are  respec- 
tively 44,  32,  28,  and  28,  we  find  that  m^  is  3.782, 


214  FUEL  OIL  AND  STEAM  ENGINEERING 

m2V2  is  3.520,  m3V3  is  .308,  and  m4V4  is  22.200.  The 
sum  of  these  products  Cs  is  found  to  be  29.810.  Hence 
since  m^V^  is  3.782,  we  now  find  that  the  carbon  diox- 
ide component  obtained  by  dividing  3.782  by  29.810 
is  .1270.  Similarly  for  the  oxygen  component  the  pro- 
portion by  weight  is  .1182;  for  the  carbon  monoxide 
component  it  is  .0103 ;  and  for  the  nitrogen  component 
we  have  .7453.  As  a  check  on  our  work  we  find  that 
the  sum  of  these  separate  components  is  unity  as  it 
should  be.  Or  expressed  in  percentages,  we  would 
have  for  a  volumetric  analysis  consisting  of  8.6  per 
cent  carbon  dioxide,  11.0  per  cent  oxygen,  1.1  per  cent 
carbon  monoxide,  and  79.3  per  cent  nitrogen,  that  the 
percentages  by  weight  become  12.70  per  cent  carbon 
dioxide,  11.82  per  cent  oxygen,  1.03  per  cent  carbon 
monoxide,  and  74.53  per  cent  nitrogen,  which  foot  up 
100  per  cent  in  either  case  and  thus  check  our  work. 

A  Suggested  Form  of  Tabulation. — To  expedite 
computation  the  work  set  forth'in  the  above  discussion 
may  be  tabulated.  Below  we  have  a  form  of  tabulation 
which  will  prove  useful  for  such  transformations : 

mV 

Constituents        Volume     Mol.  Wt.      mV  


Cs 
CO2  .086          44  3.782  .1270 

(X  .110          32  3.520  .1182 

CO"  .011  28  .308  .0103 

N,  .793          28          22.200  .7453 


1.000  Cs  =  29.810          1.0000 

Weight  of  Air  Theoretically  Required  for  Perfect 
Fuel  Oil  Combustion. — For  economic  combustion  in 
the  furnace  a  certain  percentage  of  air  over  and  above 
that  theoretically  required  for  perfect  combustion  is 
necessary.  This  is  due  to  the  fact  that  it  is  practically 
impossible  to  bring  all  of  the  entering  air  into  intimate 
contact  with  the  heated  carbon,  hydrogen,  and  other 
combustible  ingredients  of  the  fuel ;  consequently, 
unless  an  excess  of  air  is  admitted  some  of  these  in- 


AIR  REQUIRED  215 

gradients  will  pass  out  of  the  chimney  unconsumed. 
Good  practice  dictates  from  15  to  20%  excess  of  air  as 
the  proper  ratio  for  economic  fuel  oil  consumption  in 
the  furnace. 

In  order  then  to  know  when  this  ratio  is  properly 
established  we  must  have  some  means  of  ascertaining 


A  PORTABLE  PYROMETER  OUTFIT 

For  the  ready  measurement  of  temperatures  in  and  about  the  power 
plant,  a  portable  type  of  pyrometer  is  often  convenient.  In  the 
illustration  shown  temperatures  may  be  read  from  200°F.  to  2200°F. 
Such  an  instrument  as  the  one  indicated  is  convenient  in  ascer- 
taining the  flue  gas  temperatures  when  the  Orsat  analysis  is  being 
taken. 

the  air  theoretically  required  for  perfect  combustion 
as  well  as  that  actually  used  in  the  furnace  per  pound 
of  fuel. 

Correction  for  Oxygen  Appearing  in  Fuel  Analy- 
sis.— In  the  composition  of  fuels  varying  quantities  of 
oxygen  (O)  are  found  by  analysis  to  be  present.  While 
in  a  sense  this  is  in  a  free  state,  still  the  hydrogen 
content  is  reduced  in  heating  value  by  an  amount  equal 
to  the  combining  weight  of  this  oxygen  (O)  with  the 
hydrogen  (H).  Experimentally  we  find  that  8  pounds 
of  oxygen  combine  with  one  pound  of  hydrogen. 
Hence,  so  far  as  heating  value  is  concerned  and  indeed 
so  far  as  outside  oxygen  may  be  required  for  combus- 
tion of  the  hydrogen,  the  actual  hydrogen  content  is 

O 

reduced  in  value  to  (H-     — ),  where  H  represents  the 


216  FUEL  OIL  AND  STEAM  ENGINEERING 

proportion  by  weight  of  hydrogen  and  O  the  propor- 
tion by  weight  of  oxygen  present  in  the  fuel. 

Oxygen  Theoretically  Required  for  Fuel  Combus- 
tion.— The  oxygen  theoretically  required  is  computed 
from  a  consideration  of  the  fundamental  chemical  re- 
actions that  take  place  in  the  furnace. 

Thus,  from  chemistry  'we  learn  that  to  completely 
burn  one  pound  of  pure  carbon  32/12ths  of  a  pound 
of  oxygen  are  required.  Again  to  burn  one  pound  of 
pure  hydrogen  8  pounds  of  oxygen  are  required.  And 
in  the  third  place  to  burn  one  pound  of  pure  sulphur 
one  pound  of  oxygen  is  required. 

If  now  one  pound  of  fuel  oil -is  found  by  analysis 

O 

to  contain  C  parts    by  weight    of  carbon',   (H  -    — ) 

8 

parts  by  weight  of  hydrogen,  and  S  parts  by  weight 
of  sulphur,  it  is  evident  that  the  weight  of  oxygen  re- 
quired per  pound  of  fuel  oil  for  perfect  combustion  is 
from  the  above  discussion 

32  O 

C  +  8(H )+S 


12  8 

Air  Required  per  Pound  of  Fuel  Burned. — Since 
air  is  composed  of  .2315  parts  by  weight  of  oxygen, 
the  theoretical  weight  of  air  Mta  necessary  to  supply 
the  oxygen  above  required  for  perfect  combustion  is 

32      1         O   1        1 
Mta  =  — 


12    .2315        8  .2315      .2315 

O 

Mta  =  11.52C  +  34.56  (H )  +  4.32  S   ....  (2) 


An  Illustrative  Example.  —  Fuel  analyses  are 
always  given  in  proportions  or  percentages  by  weight. 
In  a  certain  boiler  test  a  sample  pound  of  the  fuel 
oil  analyzed  as  follows:  carbon  81.52%;  hydrogen 
11.01%;  sulphur  .55%;  and  oxygen  6.92%.  Let  us 


AIR  REQUIRED  217 

then  compute  the  weight  of  air  Mta  theoretically  re- 
quired to  burn  a  pound  of  this  oil. 

In  applying  the  formula  above  deduced,  it  must 
be  remembered  that  the  symbols  there  given  for  hy- 
drogen, oxygen,  and  sulphur  contents  are  in  propor- 
tions and  not  percentages.  Bearing  this  in  mind  we 
have  by  substitution — 

.0692 
Mta  =  .11.52  X  -8152  +  34.56  (.1101  -  -)  + 

8 
4.32  X  -0055  =  12.92  Ib. 

Having  now  learned  how  to  convert  the  Orsat 
analysis  by  volume  into  proportions  by  weight  and 
also  to  ascertain  the  air  theoretically  required  per 
pound  of  fuel,  we  shall  in  the  next  discussion  deter- 
mine actual  combustion  data  by  means  of  these  step- 
ping stones  in  computation. 


CHAPTER   XXVI 

COMPUTATION    OF   COMBUSTION    DATA 
FROM  THE  ORSAT  ANALYSIS 


N  the  last  chapter  the  read- 
er was  shown  in  detail 
how  to  convert  the  Orsat 
analysis  by  volume  to  an 
analysis  by  weight.  We 
now  assume  that  the  vol- 
umetric content  of  a  sam- 
ple of  flue  gas  has  been 
taken  and  that  Vx,  V2,  V3 
and  V4  represent  quanti- 
tatively the  carbon  diox- 
ide, oxygen,  carbon  mo- 
noxide, and  nitrogen  con- 
tents respectively. 

If  accurately  ascertained 
these  components  of  the 
flue  gas  enable  the  engi- 
neer, as  has  been  previous- 

ly   hinted,   to   compute   im- 
chimney      portant   economic     COnclu- 

sions    on   the    combustion 

phenomena  that  are  taking  place  in  the  boiler  furnace. 
It  is  important  to  know,  for  instance,  not  only  the  air 
that  is  theoretically  required  for  perfect  combustion, 
but  the  actual  weight  of  air  that  is  being  admitted  to 
the  furnace  per  pound  of  fuel  consumed.  The  weight 
of  the  flue  gases  per  pound  of  fuel  burned  is,  too,  of 
importance,  as  well  as  many  other  details  that  may 
now  be  ascertained.  Several  different  methods  of  util- 
izing the  flue  gas  analysis  have  been  proposed  to  ar- 
rive at  combustion  data.  Let  us  now  proceed  to  their 
consideration  and  discussion. 


Boiler  Front—  Oil  fired;  showing 
gage    for     measuring- 


218 


COMBUSTION  DATA  219 

Air  Actually  Supplied  to  Furnace  per  Pound  of 
Fuel  Burned. — There  are  three  formulas  that  enable 
us  to  compute  the  actual  quantity  of  air  entering  the 
furnace  if  we  know  the  analysis  of  the  chimney  gases. 

From  volumetric  experiments  in  chemistry  we 
learn  that  V^  units  by  volume  of  oxygen  form  V±  units 
by  volume  of  carbon  dioxide,  thereby  burning  Vx  units 
by  volume  of  carbon  in  the  fuel. 

On    the    other   hand,    volumetric   experiments    in 

V8 

chemistry  tell  us  that  —    -  units  by  volume  of  oxygen 

2 

form  V3  units  by  volume  of  carbon  monoxide,  thereby 
burning  V3  units  by  volume  of  carbon  in  the  fuel. 

Again,  V2  units  of  oxygen  appearing  in  the  flue 
gas  have  evidently  necessitated  the  entrance  of  V2 
units  of  oxygen  from  the  air  without,  but  have  re- 
quired no  carbon  from  the  fuel. 

V3 

Summing  up,  we  find  that  (Vx-|--   -  +  V2)   units 

2 

by  volume  of  oxygen  have  required  (V1+V3)  units  by 
volume  of  carbon  in  the  fuel  for  the  formation  of  the 
particular  analysis  shown  in  the  flue  gas. 

Therefore,  one  unit  by  volume  of  carbon  in  the 
fuel  would  require 

V3 

VH i-v, 


v,  +  v, 

units  by  volume  of  entering  oxygen. 

A  unit  volume  of  carbon,  however,  weighs  12 
pounds,  while  a  similar  unit  volume  of  oxygen  weighs 
32  pounds.  Hence,  for  every  unit  weight  of  carbon 
consumed  in  the  furnace 


32  2 

—  X 

12  V,  +  V 


220  FUEL  OIL  AND  STEAM  ENGINEERING 

units  by  weight  of  oxygen  are  required.  Air  has  by 
weight  .2315  proportions  of  oxygen.,  Hence  if  C  units 
by  weight  of  carbon  are  found  in  each  pound  of  fuel. 
the  actual  weight  of  air  Mc  admitted  to  the  furnace  to 
burn  carbon  per  pound  of  fuel  burned  is 

V3 

vx+-    -+v2 

32          1  2 

_         V  v  _  \s  C 

c  —         /\~~~~/\~  ~~  /\  ^ 

12       .2315  V        V 


V3 

-      V 


/.  M.=  11.S2X-  -XC  ......  (1) 

v>  +  v, 

It  is  to  be  remembered  that  the  derivation  of  this 
formula  thus  far  has  not  taken  into  account  the  hydro- 
gen content  of  the  fuel.  Since  the  Orsat  analysis  con- 
denses the  water  vapor  formed  by  the  burning  of  the 
hydrogen  with  the  entering  oxygen  of  the  air  as  the 
sample  enters  the  first  tube  of  the  apparatus,  the  ac- 
tual Orsat  analysis  indicates  volumetric  proportions 
for  the  dry  flue  gas  only.  We  can,  however,  if  we 
know  the  hydrogen  content  present  in  the  fuel,  make 
^  correction  or  rather  addition  to  the  above  formul?. 
so  that  the  relationship  will  correctly  represent  the  to- 
tal admission  of  air  into  the  furnace  under  test. 

In  the  previous  chapter  it  was  shown  that  if  a  fuel 
analysis  indicates  H  units  of  hydrogen  by  weight  and 
O  units  of  free  oxygen  by  weight  that  the  actual 

O 

hydrogen  available  for  combustion  is   (H—    —  )   units 
by  weight. 

It  has  been  seen  too  that  one  pound  of  hydrogen 
requires  for  its  burning  eight  pounds  of  oxygen,  and 
that  air  contains  .2315  proportions  by  weight  of 
oxygen.  Hence  the  weight  of  air  necessary  to  burn 


COMBUSTION  DATA  221 

O  80 

(H-     —  )    pounds  of  hydrogen  is—        -  (H—    —  )    or 
8  .2315  8 

O 

34.56  (H-     -)  pounds. 
8 

Therefore,  the  total  air  Ma  admitted  to  the  fur- 
nace per  pound  of  fuel  oil  burned  is 


2  O 

Ma=11.52X-  -  XC+34.S6(H  --  )  ..(2) 

V,  +  V3  8 

An  Illustrative  Example.  —  A  certain  California  oil 
by  chemical  analysis  is  found  to  contain  81.52%  car- 
bon; 11.01%  hydrogen;  .55%  sulphur;  and  6.92% 
oxygen.  The  flue  gas  of  a  boiler  under  test  using  this 
oil  was  found  by  Orsat  anaylsis  to  contain  8.6%  car- 
bon dioxide;  9.0  %  oxygen;  1.1%  carbon  monoxide; 
and  81.3  per  cent  nitrogen.  Let  us  by  means  of  the 
above  formula  compute  the  air  actually  admitted  to 
the  furnace  per  pound  of  oil  burned  in  the  test.  Before 
substitution  we  must  remember  that  the  above  for- 
mula is  expressed  in  proportions  and  not  in  percent- 
ages. Substituting  then,  writh  this  in  mind,  we  have 

.086  +  .0055  +  .09 

Ma  =  11.52  X  -  X  -8152 
.086  +  .011 

.0692 

+  34.56  X  (-1101-         -)=21.11b. 
8 

A  Second  Formula  for  Ascertaining  Air  Actually 
Admitted  to  the  Furnace.  —  Let  us  next  deduce  a  for- 
mula recommended  by  the  American  Society  of  Me- 
chanical Engineers  for  the  determination  of  the  air 
supplied  to  the  furnace  per  pound  of  fuel  consumed. 

In  the  deduction  of  the  last  formula  it  was  seen 
that  the  entering  oxygen  combines  with  ( 


FUEL  OIL  AND  STEAM  ENGINEERING 

units  by  volume  of  carbon  in  the  fuel.  With  this  en- 
tering oxygen,  however,  is  associated  V4  units  by 
volume  of  nitrogen.  Hence  for  each  unit  by  volume 


of  carbon  consumed  in  the  furnace  (—  — )  units  by 

V1+V3 

volume  of  nitrogen  enter  with  the  oxygen  into  the  fur- 
nace. Since  one  unit  of  carbon  by  volume  weighs 
12/28ths  of  the  weight  of  one  unit  by  volume  of  ni- 
trogen, we  have  that  for  every  pound  of  carbon  burned 
in  the  furnace 

28  V4 

-x 

12      V,  -I-  Vo 


pounds  of  nitrogen  enter  from  without.  But  air  is 
.7685  parts  by  weight  nitrogen.  Hence  if  fuel  oil  con- 
tains C  parts  by  weight  of  carbon,  for  every  pound  of 
fuel  oil  burned  in  the  furnace,  the  weight  of  air  Ma 
diawn  in  from  without  is 

28V4  1 

Ma  =    C    X 


12  (VH-V.)       7685 

V4 

.'.  Ma  =  3.032(-  -)   C   (3) 

Vi  +  V. 

An  Illustrative  Example. — Taking  as  an  example 
the  data  set  forth  in  illustrating  the  first  formula  de- 
duced for  ascertaining  the  air  actually  admitted  to  the 
furnace,  we  have  by  substituting  in  this  second  for- 
mula that 

.813 

Ma  =  3.032  (-         — — )   .8152  =  20.7  Ibs. 
.086 +  .011 

Weight  of  Dry  Flue  Gas  per  Pound  of  Fuel. — 

Since  the  entering  air  above  computed  combines  with 
one  pound  of  fuel,  we  may  ascertain  the  weight  of  flue 
gas  per  pound  of  fuel  oil  consumed  by  simply  adding 


COMBUSTION  DATA  223 

unity  to  the  weight  of  air  actually  admitted  to  the 
furnace. 

Let  us,  however,  deduce  a  formula  directly  for 
this  computation  and  check  by  numerical  comparison 
the  results  obtained  by  the  former  methods. 

To  convert  an  analysis  by  volume  into  an  analysis 
by  weight  it  has  been  shown  that  if  these  components, 
carbon  dioxide  (CO2),  oxygen  (O2),  carbon  monoxide 
(CO),  and  nitrogen  (N2)  are  respectively  Vx,  V2,  V3 
and  V4  by  volume,  then  by  weight  according  to  the  for-. 
mula  derived  in  the  last  discussion,  they  will  prove  to 
be 

II^Y!    m2V2    m3V3  m4V4 

_      _      __       o  n  H 

,  ,  ,     dllU.  , 

cs      cs      cs  c, 

wherein  Cs  is  obtained  by  summing  up  all  products 
formed  by  multiplying  each  component  volume  by  its 
molecular  wTeight.  For  every  pound  of  carbon  dioxide 
(CO2)  formed  12/44  Ib.  of  carbon  are  consumed  in  the 


fuel  oil.    Hence  to  form  -         -  Ib.  of  carbon  dioxide  it 

Cs 

12          m.V, 

is  evident  that  (—    -  of  -         —  )  Ib.  of  carbon  are  con- 
44  Cs 

sumed  in  the  fuel  oil.  But  mx  for  carbon  dioxide  (CO2) 

12V, 
is  44.     Hence  this  quantity  becomes 


Cs 

Similarly,  since  each  pound  of  carbon  monoxide 
(CO)    in  its   formation   requires   12/28   Ib.   of   carbon 

m3V3 

from  the  fuel  oil,  for  the  formation  of  -         -  Ib.  of  car- 

Cs 

12         m3V3 

bon  monoxide  (CO),  we  must  burn  ( —  of  -        — )  Ib. 

28  Cs 


224  FUEL  OIL  AND  STEAM  ENGINEERING 

of  carbon.     But  m3  for  carbon  monoxide  (CO)  is  28. 

12V, 

Hence  this  quantity  becomes 


Cs 

The  free  oxygen  and  the  free  nitrogen  in  the  flue 
gas  have  of  course  required  no  carbon  of  the  fuel. 
Therefore,  for  M  Ib.  of  chimney  gas  there  will  be  re- 
quired 

12V,  12V3  12 

+  -  (V1  +  V3) 

cs  cs        cs 

units   of   carbon ;   or  recipracally,   one  pound  of  car- 

Cs 

bon  will,  of  course,  form  -  -  units  by  weight 

12(V1  +  V3) 

of  flue  gas  and  C  parts  of  carbon  by  weight  in  the  fuel 
wi1!  form  Mg  Ib.  of  flue  gas  which  may  be  computed 
from  the  formula 

Cs 

Mg  =  C  


But  the  molecular  weight  for  carbon  dioxide  is 
44,  for  oxygen  it  is  32,  for  carbon  monoxide  it  is  28, 
and  for  nitrogen  it  is  28,  therefore  for  Cs  we  have 

Cs  =  44V,  +  32V2  +  28V3  +  28V4 

44V,  +  32V,  +  28V3  +  28V4 
or  M,  =  C 


.'.Mg  =  C  -  (4) 

3(V±  +  V3) 

An  Illustrative  Example. — Let  us  now  use  the 
same  experimental  data  as  in  the  previous  examples 
and  compute  the  pounds  of  dry  flue  gas  that  were 
formed,  as  indicated  by  the  data  from  the  Orsat  an- 
alysis. 


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Tf 

3 

0 

^ 

> 

BJ 

0) 

0 

^ 

c 

i. 

+-J" 

Ul 

1 

rt 

'EJc 

5 

O    0)     « 
^     n    "t\ 


""So 


lollS 

c          ^  », 


^  *J 


COMBUSTION  DATA  225 

It  is  to  be  noted  in  passing  that  all  of  these  com- 
putations based  simply  upon  the  .Orsat  analysis  give 
the  weight  of  dry  flue  gas  only.  If  the  moisture  pres- 
ent in  the  flue  gas  is  to  be  taken  into  consideration,  a 
correction  should  be  made  by  noting  the  hydrogen 
present  in  the  fuel,  the  moisture  in  the  entering  air, 
and  the  steam  used  in  atomization.  In  ordinary  prac- 
tice these  factors  are  not  used,  for,  as  we  shall  see  in 
the  discussion  of  the  heat  balance  in  a  later  chapter, 
the  moisture  content  is  properly  cared  for  under  sep- 
arate headings.  Returning  to  our  example,  then,  we 
find  that  the  weight  of  dry  flue  gas  Mg  per  pound  of 
fuel  burned  is 


11  X-086  +  8X-09  +  7X-OH  +  7X-813 
- 

3  (.086  +  .011) 
=  20.8 

Ratio  of  Air  Drawn  Into  Furnace  to  that  Theoret- 
ically Required.  —  We  have  already  derived  sufficient 
relationships  to  compute  the  ratio  of  air  drawn  into 
the  furnace  to  that  theroetically  required.  Let  us, 
however,  proceed  to  the  derivation  of  another  formula 
that  is  recommended  for  use  by  the  American  Society 
of  Mechanical  Engineers  in  the  testing  of  boilers. 

Assuming  that  perfect  combustion  is  taking  place 
and  neglecting  the  hydrogen  content  of  the  fuel  which 
we  know  disappears  in  the  Orsat  apparatus  before  our 


analysis  really  begins,  we  have  that  for  -          -  Ib.  of 

-Cs 

m4V4         1 

nitrogen  drawn  into  the  furnace  -  -  Ibs.  of 

Cs       7685 

air    must    have    passed    in.      Similarly,    if    no    carbon 


monoxide  is  formed  in  the  flue  gas,  for  -          -  Ib.  of 

Cs 


226  FUEL  OIL  AND  STEAM  ENGINEEHING 

free  oxygen  appearing  in  the  flue  gas,  then  evidently 


m2V2 


Cs  .2315 


of  excess  air  must  also  have  been 


drawn  into  the  furnace.    Hence  we  have  that  the  total 
air  Ma  drawn  in  is  expressed  by  the  formula 

Ma  =  -^-^ 


Cs        .7685 
While  the  air  Mta  theoretically  required  is 

m4V4          1  m2V2 

Mta  = 


Cs        .7685  Cs        .2315 

Therefore,  the  ratio  ra  of  the  air  actually  supplied 
to  that  theoretically  required  may  be  derived  as  fol- 
lows : 


Ma  Cs        .7685 


Mta 


Cs        .7685  Cs       .2315 

1 
m±V4 

.7685 

1  1 

m4V4  .  —  -  iruVo 

.7685  .2315 


Since  m4  =  28  and  m2  =  32,  we  have 

V4  V4 


ra  = 


32V2        .7685         V4  —  3.782  V: 
V4- 

28         .2315 


...(5) 


COMBUSTION  DATA  227 

An  Illustrative  Example. — Using  the  same  data 
as  employed  in  previous  examples,  we  have 

.813 

ra  =  =  172 


.813  —  3.782  X  -09 

The  air  theoretically  required  in  this  example  was 
computed  on  page  217  and  found  to  be  12.92  Ib. 
Hence  for  the  three  formulas  derived  we  arrive  at  the 
following  values  for  ra : 

From  formula  (2)  Ma  was  found  to  be  21.1. 

21.1 

.'.  ra  = =  1.63 

12.92 

From  formula  (3)  Ma  was  found  to  be  20.7. 

20.7 

.'.  ra  =  =  1.60 

12.92 

And  from  formula  (4)  IVL  was  found  to  be  20.8. 
Hence  Ma  is  19.8  and 

19.8 

.'.  r.  =  -       -=  1.53 
12.92 

It  is  difficult  to  pick  the  most  correct  formula  to 
use  in  any  given  instance.  If  the  analyses  are  ob- 
tained with  precision,  undoubtedly  results  will  be  ob- 
tained that  will  check  quite  closely — indeed  well  with- 
in the  degree  of  precision  of  the  other  factors  that 
enter. 

With  the  combustion  data  thus  obtained,  we  are 
now  in  position  to  proceed  to  the  determination  of  the 
heat  balance  which,  as  we  shall  see  later,  tells  us  in  de- 
tail just  what  disposition  is  being  made  of  the  vast 
quantities  of  heat  that  are  generated  in  the  furnace 
due  to  the  burning  of  the  fuel  oil. 

It  is  sometimes  convenient  to  be  able  to  determine 
in  advance  the  maximum  amount  of  CO2  that  can  be 
expected  in  the  flue  gas  when  burning  oil  with  a  given 
quantity  of  excess  air.  In  the  following  table  three 


228 


FUEL  OIL  AND  STEAM  ENGINEERING 


different  cases  of  the  combustion  of  one  pound  of  oil 
are  worked  out,  the  excess  air  being  taken  at  zero  in 
the  first  case,  50%  in  the  second  and  100%  in  the 
third.  In  all  three  cases  it  is  assumed  that  perfect 
combustion  is  obtained,  thus  eliminating  CO  from  the 
ca'culations  and  that  J/£  pound  steam  per  pound  of  oil 
is  used  for  atomization.  It  is  also  assumed  that  the 
fuel  oil  contains  85%  Carbon  and  11%  Hydrogen,  the 
Other  ingredients  being  neglected.  The  calculations 
do  not  require  any  explanation,  as  they  can  be  easily 
followed,  the  ingredients  of  the  air  and  fuel  being  seg- 
regated and  combined  in  proper  proportions  according 
to  chemical  formulae,  and  then  converted  from  weight 
to  volume,  and  to  per  cent  by  volume  as  ordinarily  ob- 
tained in  flue  gas  analysis. 


Combustion  of  One   Pound   of  Oil 


Air  supplied  per  Ib.   oil Lbs. 

Oxygen  supplied  per  Ib.  oil.  .  .  .Lbs. 
Nitrogen  supplied  per  Ib.  oil.  .Lbs. 
Oxygen  used  per  Ib.  oil Lbs. 


Oxygen   free    Lbs. 

CO2    produced    Lbs. 

H2O  from   combustion. .  .Lbs. 
H2O  from  atomizing 

steam  Lbs. 

Nitrogen   supplied    Lbs. 

Total  weight  of  gases... Lbs. 


Oxygen— Vol.  at  32°  ..  .Cu.  ft. 

CQ2 — Vol.    at    32° Cu.  ft. 

H2O— Vol.  at  32° Cu.  ft. 

Nitrogen — Vol.  at  32°..Cu.  ft. 
Total  Vol.   at  32° Cu.  ft. 


No 
Excess 
Air 

50% 
Excess 
Air 

100% 
Excess 
Air 

13.21 
3.06 
10.15 
3.06 

19.81 
4.59 
15.22 
3.06 

26.42 
6.12 
20.30 
3.06 

No 
Excess 
Air 

50% 
Excess 
Air 

100% 
Excess 
Air 

0. 

1.53 

3.06 

3.00 

3.00 

3.00 

.99 

.99 

.99 

.5 

10.15 
14.64 


0. 
24.3 


.5 
15.22 

21.24 


17.1 
24.3 
Negligible 
129.2  194.1 

153.5  235.5 


.5 

20.30 
27.85 

34.3 
24.3 

258.5 
317.1 


Oxygen — Per  cent,  by  volume  0.  7.26  10.81 

CO2— Per  cent,  by  volume...  15.8  10.32  7.66 

Nitrogen— Per  cent  by  volume  84.2  82.42  81.53 


CHAPTER   XXVII 


WEIGHING  THE   WATER   AND    OIL   IN 
BOILER    TESTS 

HERE  are  various  types 
of  commercial  water 
meters  and  water  weigh- 
ers on  the  market.  Some 
of  these  are  quite  accu- 
rate for  certain  investiga- 
tions. For  boiler  per- 
formance, however,  they 
are  not  to  be  recom- 
mended. 

Volumetric  Method  of 
Water    Measurement.  — 

Water  may  also  be  meas- 
ured quantitatively  by 
taking  its  volumetric  pro- 
portions. Its  weight  is 
then  computed  after  as- 
certaining its  s  p  e  c  i  f  i  c 
density.  The  reverse  of 
this  principle  is  used,  for 
instance,  in  measuring 
the  volumetric  clearance  of  a  steam  engine,  where- 
in water  is  poured  into  the  cylinder  ports  when  the 
p;ston  head  is  at  its  dead  end  and  the  water  afterwards 
drained  out  and  weighed.  From  the  weight  of  the 
water  so  used  the  volume  of  the  clearance  is  computed. 
In  rough  measurements  of  engine  and  boiler  perform- 
ance the  water  is  sometimes  measured  by  filling  a  tank 
or  barrel  of  known  volumetric  proportions,  and  by 
keeping  account  of  the  number  of  barrels  so  filled  and 
dumped  into  the  sump,  sufficient  data  is  obtained  to 
compute  the  weight. 

229 


Tank  in  rear  for  weighing  oil 


230 


FUEL  OIL  AND  STEAM  ENGINEERING 


The  Method  of  Standardized  Platform  Scales.— 

It  is  now  universally  recognized,  however,  that  care- 
fully weighing  the  water  on  carefully  standardized 
scales  is  the  only  safe  and  reliable  method  of  ascertain- 


s  '. 

An  Excellent  Design  for  a  Measuring  Tank 

ing  the  water  fed  to  a  boiler  under  test. 

Let  us  then  see  how  the  details  are  arranged  for 
the  weighing  of  the  water  used  in  steam  generation. 


WEIGHING  WATER  AND  OIL 


231 


A  large  square  metallic  tank  about  5  by  5  by  4 
feet  in  dimensions  is  usually  constructed.  From  the 
bottom  of  this  tank  all  feed  water  for  steam  generation 
in  the  boiler  under  test  is  drawn.  At  the  beginning 
of  the  test  the  water  level  in  this  tank  is  accurately 
measured  by  means  of  a  hook  gage  situated  within 
the  tank.  At  the  end  of  each  hourly  period  of  the 
test  and  at  the  conclusion  of  the  test  this  exact  level 
is  also  maintained. 

The  control  for  the  water  supply  is  accomplished 
by  two  or  three  vertical  cylindrical  tanks  that  have 


A    DESIGN    FOR    A    WEIGHING    TANK    IN    A    BOILER    TEST 

In  order  to  assure  the  rapid  passage  of  water  or  oil  from  the  tank 
upon  the  platform  scales  into  the  container  below,  the  employment 
of  steel  tanks  with  conical  shaped  bottoms  is  most  effective.  The 
outlet  for  the  oil  or  water  should  be  controlled  by  quick-opening 
valves. 

a  conically  shaped  outlet  at  the  bottom.  These  tanks 
are  located  on  standardized  scales  immediately  above 
the  main  supply  tank  that  has  just  been  described. 
The  complete  installation  is  shown  in  the  illustration. 
At  the  beginning  of  the  test  the  height  of  the  water 
in  the  boiler  is  noted  on  the  gage  glass  in  front  of  the 
boiler  and  as  near  as  is  possible  the  feed  pump  is  reg- 
ulated in  its  operation  so  as  to  maintain  this  level.  At 
the  instant  of  conclusion  the  water  level  is  most  care- 
fully adjusted  to  meet  the  condition  of  boiler  water 
level  prevailing  at  the  beginning  of  the  test. 


FUEL  OIL  AND  STEAM  ENGINEERING 

As  the  water  is  drawn  from  the  feed  tank  beneath 
the  platform  scales  the  operators  fill  the  tanks  on  the 
scales  above  and  note  the  weight  before  and  after 
emptying  their  contents  into  the  tank  below.  Thus 
with  ease  the  water  surface  in  the  tank  below  may 
be  kept  at  the  constant  hook  gage  reading  desired, 
and  the  net  weight  of  water  fed  to  the  boiler  ascer- 
tained at  any  time  during  the  test. 

The  improvised  desk  boards  shown  in  the  illustra- 
tion assist  materially  in  aiding  the  water  weighing 
operators  to  perform  their  task  with  ease  and  without 
confusion. 

In  order  to  prevent  wastes  and  leakages  of  water, 
it  is  well  to  disconnect  the  outlets  from  the  blowoff 
pipes  of  the  boiler  during  the  period  of  the  test.  All 
outlets  from  the  water  columns  and  gage  glasses 
should  also  be  carefully  watched. 

The  Weighing  of  the  Oil. — For  the  careful  weigh- 
ing of  the  oil  fed  to  the  furnace  a  similar  device  is  con- 
structed as  in  the  case  of  the  water  determination.  A 
metallic  tank  is  constructed  from  which  the  oil  supply 
is  pumped  to  the  furnace  through  the  oil  heater.  The 
oil  pump  is  best  fitted  with  a  governor  and  an  auto- 
matic relief  valve.  By  this  means  a  constant  pressure 
may  be  maintained  on  the  oil  line  to  the  burners.  The 
discharge  from  the  relief  valve  is  led  back  to  the  tank 
from  which  the  supply  to  the  pump  is  taken.  Within 
the  tank  is  situated  a  hook  gage,  the  reading  of  which 
is  carefully  ascertained  at  the  instant  of  the  begin- 
ning of  the  test.  This  exact  reading  is  maintained 
throughout  the  hourly  progress  of  the  test,  and  indeed 
at  any  other  period  if  so  desired. 

This  is  accomplished  by  means  of  a  tank  situated 
above  the  main  supply  tank.  This  tank  is  installed 
on  standardized  scales.  Previous  to  the  discharge  of 
the  oil  into  the  tank  below,  the  scales  are  read  and 
when  the  oil  is  brought  to  the  proper  hook  gage  read- 
ing in  the  tank  below,  the  scales  are  again  read.  By 
subtracting  these  two  readings,  the  net  oil  supply  is 
ascertained. 


WEIGHING  WATER  AND  OIL  233 

Sampling  the  Oil  Supply. — As  the  fuel  is  poured 
into  the  tank  upon  the  standardized  scales,  a  dipperful 
of  the  oil  is  set  aside  in  a  convenient  receptacle.  After 
a  sample  has  thus  been  obtained  from  each  tank,  as  it 
is  weighed,  the  entire  quantity  is  then  thoroughly 
mixed.  Three  parts  of  this  mixture  are  then  put  into 
separate  cans  and  sealed.  One  part  is  analyzed  by  the 
party  or  company  for  whom  the  test  is  being  per- 
formed, the  second  is  analyzed  by  a  disinterested  party, 
and  the  third  is  retained  in  case  of  disagreement. 

General  Sampling  of  Fuel  Oil  for  Purchase. — The 

question  of  determining  a  proper  sample  for  commer- 
cial valuation  of  oil  is  one  of  patient  care.  The  United 
States  Bureau  of  Mines  has  evolved  careful  instruc- 
tions to  accomplish  this  in  their  technical  paper  No.  3, 
from  which  the  following  is  largely  an  excerpt : 

The  accuracy  of  the  sampling  and,  in  turn,  the 
value  of  the  analysis  must  necessarily  depend  on  the 
integrity,  alertness  and  ability  of  the  person  who  does 
the  sampling.  No  matter  how  honest  the  sampler  may 
be,  if  he  lacks  alertness  and  sampling  ability,  he  may 
easily  make  errors  that  will  vitiate  all  subsequent  work 
and  render  the  results  of  tests  and  analyses  utterly 
misleading.  A  sampler  must  be  always  on  the  alert 
for  sand,  water  and  foreign  matter.  He  should  note 
any  circumstances  that  appear  suspicious,  and  should 
submit  a  critical  report  on  them,  together  with  sam- 
ples of  the  questioned  oil. 

Sampling  With  a  Dipper. — Immediately  after  the 
oil  begins  to  flow  from  the  wagon  to  the  receiving 
tank,  a  small  dipper  holding  any  definite  quantity,  say 
0.5  liter  (about  1  pint),  is  filled  from  the  stream  of 
oil.  Similar  samples  are  taken  at  equal  intervals  of 
time  from  the  beginning  to  the  end  of  the  flow  —  a 
dozen  or  more  dipperfuls  in  all.  These  samples  are 
poured  into  a  clean  drum  and  well  shaken.  If  the  oil 
is  heavy,  the  dipperfuls  of  oil  may  be  poured  into  a 
clean  pail,  and  thoroughly  stirred.  For  a  complete 
analysis  the  final  sample  should  contain  at  least  4 
liters  (about  1  gallon).  This  sample  should  be  poured 


234 


FUEL  OIL  AND  STEAM  ENGINEERING 


into  a  clean  can,  soldered  tight  and  forwarded  to  the 
laboratory. 

It  is  important  that  the  dipper  be  filled  with  oil 
at  uniform  intervals  of  time,  and  that  the  dipper  be 
always  filled  to  the  same  level.  The  total  quantity  of 
oil  taken  should  represent  a  definite  quantity  of  oil 
delivered  and  the  relation  of  the  sample  to  the  deliv- 


/'       ~N 

,                    \ 

(    *">"«•   \ 

Doon 

OUTLET 

AN  EXCELLENT  WATC.R  MEASURER 

While  the  automatic  water  measurer  is  not  as  accurate  as  the 
standardized  scale  method,  still  it  finds  many  applications  in  the 
testing-  laboratory. 

ery  should  be  always  stated,  for  instance:  "1-gallon 
sample  representing  1  wagon-load  of  20  barrels." 

Continuous  Sampling. — Instead  of  taking  samples 
with  a  dipper,  it  may  be  more  convenient  to  take  a  con- 
tinuous sample.  This  may  be  taken  by  allowing  the 


WEIGHING  WATER  AND  OIL  235 

oil  to  flow  at  a  constant  and  uninterrupted  rate  from  a 
5^-inch  cock  on  the  underside  of  the  delivery  pipe  dur- 
ing the  entire  time  of  discharge.  The  continuous  sam- 
ple should  be  thoroughly  mixed  in  a  clean  drum  or 
pail,  and  at  least  4  liters  (about  1  gallon)  of  it  for- 
warded for  analysis.  A  careful  examination  should  be 
made  for  water,  and  if  the  first  dipperful  shows  water 
this  dipperful  should  be  thrown  into  the  receiving 
tank  and  not  mixed  with  the  sample  for  analysis. 

Mixed  Samples. — The  all-important  point  is  that 
the  gross  sample,  whatever  the  manner  of  sampling, 
shall  be  made  up  of  equivalent  portions  of  oil  taken 
at  regular  intervals  of  time,  so  that  the  sample  finally 
forwarded  for  analysis  will  truly  represent  the  entire 
shipment. 

Water  or  earthy  matter  settles  on  standing. 
Hence,  before  a  large  stationary  tank  or  a  reservoir  is 
sampled,  the  character  of  the  contents  at  the  bottom 
should  be  ascertained  by  dredging  with  a  long-handled 
dipper,  and  the  contents  of  the  dipper  should  be  ex- 
amined critically.  If  a  considerable  quantity  of  sedi- 
ment is  brought  up,  it  should  be  cause  for  rejecting 
the  oil. 


THE    VISCOSIMETER 

The  design  of  this  viscosi- 
meter  is  based  upon  a  thor- 
ough knowledge  of  lubricat- 
ing oils  and  of  the  require- 
ments of  manufacture  and 
trade.  It  is  made  to  meet  all 
demands  as  a  measure  of 
viscosity,  and  is  without  the 
many  objections  that  may  be 
made  to  all  other  devices  for 
this  purpose.  The  viscosity 
of  any  oil  is  shown  by  the 
number  of  seconds  required 
for  a  certain  number  of 
cubic  centimeters  to  run 
through  the  open  faucet. 
This  corresponds  to  the  most 
generally  approved  standard 
now  in  use  by  the  largest  re- 
finers. (See  page  136) 


CHAPTER   XXVIII 

MEASUREMENT   OF   STEAM   USED   IN 
ATOMIZATION 

As  has  been  previously  set  forth,  there  are  three 
methods  used  in  pulverizing  or  atomizing  the  fuel  oil 
in  the  industries  for  heat  generating  purposes,  namely : 


A  Typical  Steam  Meter 

by  compressed  air,  by  steam,  and  by  some  mechanical 
operation. 

In  any  one  of  these  instances  the  actual  expendi- 
ture of  energy  necessary  to  accomplish  this  result 
when  converted  into  heat  units'  should  be  charged 
as  a  loss  in  furnace  operation,  when  the  efficiency  of 


982 


STEAM  IN  ATOMIZATION  237 

the  boiler  as  a  whole  is  being  determined.  And  if  this 
energy  is  taken  from  the  steam  that  is  being  generated 
in  the  boiler,  then  the  net  steam  energy  should  be 
computed  by  subtracting  from  the  gross  production 
such  steam  as  may  be  used  in  atomization. 

It  then  becomes  the  task  of  the  steam  engineer 
to  construct  some  accurate  and  convenient  apparatus 
whereby  this  may  be  easily  and  accurately  accom- 
plished. 

There  are  steam  meters  on  the  market  that  may 
be  utilized  for  this  p'urpose,  and  if  a  careful  design 
is  picked,  the  measurement  may  be  relied  upon.  Many 
engineers,  however,  prefer  the  use  of  a  standardized 
orifice  or  the  construction  of  an  apparatus  of  their  own 
whereby  this  important  data  may  be  ascertained  with 
accuracy. 

Mathematical   Expression  for   Flow   of   Steam. — 

In  the  mathematical  considerations  involved  in  estab- 
lishing a  formula  for  steam  flow  through  orifices,  a 
rather  unique  incident  is  encountered.  When  the 
pressure  of  the  lower  medium  into  which  the  steam 
empties  itself  is  less  than  58  per  cent  of  the  higher 
pressure,  a  certain  formula  applies.  And  the  rather  re- 
markable thing  is  that  below  this  point  the  flow  is 
neither  increased  nor  decreased  by  a  reduction  of  the 
external  pressure,  even  to  the  extent  of  a  perfect 
vacuum.  This  was  the  basis  upon  which  Napier's  for- 
mula was  derived  in  the  chapter  on  Steam  Calorimetry, 
wherein-  a  formula  was  given  to  compute  the  steam 
titilized  for  operating  the  calorimeter.  In  this  for- 
mula is  was  seen  that,  if  W  is  the  weight  of  the  steam 
in  pounds  per  second  flowing  into  the  atmosphere,  p 
the  absolute  pressure  in  pounds  per  square  inch  in  the 
steam  main,  and  a  the  area  of  orifice  in  square  inches, 
wre  have 

pa 

W  =  -     -  (1) 

70 

For  steam  flowing  through  an  orifice  from  a  high- 
er to  a  lower  pressure  where  the  lower  pressure  is 


238 


FUEL  OIL  AND  STEAM  ENGINEERING 


greater  than  58  per  cent  of  the  higher,  we  have  the 
formula 


W  =  1.9  AK  [/  (P-  d)d 


(2) 


wherein  W  is  the  weight  of  steam  as  discharged  in 
pounds  per  minute,  A  the  area  of  orifice  in  square 
inches,  P  the  absolute  initial  pressure  in  pounds  per 


APPARATUS    EMPLOYED    IN    MEASURING   STEAM    IN 
ATOMIZATION 

The  flow  of  steam  through  an  orifice  wherein  a  slightly  lower 
pressure  is  maintained  on  the  further  side  of  the  orifice,  is  found 
experimentally  to  be  proportional  to  the  difference  in  mercury 
heights  indicated  on  the  manometer  shown  on  the  right  in  the  il- 
lustration. By  calibrating  these  readings  prior  to  a  test  the  steam 
used  in  atomization  may  be  conveniently  and  readily  determined 
during  a  test. 

square  inch,  d  the  difference  in  pressure  between  the 
two  sides  in  pounds  per  square  inch,  and  K  is  a  con- 
stant which  has  a  value  of  .93  for  a  short  pipe  and  .63 
for  a  hole  in  a  thin  plate  or  a  safety  valve. 

This  latter  formula  is  applicable  in  the  measure- 
ment of  steam  to  burner  utilized  in  the  atomization 
of  fuel  oil.  In  the  following  lines  a  method  will  be 
outlined  setting  forth  the  necessary  apparatus  in- 
volved in  determining  the  variables  in  the  formula. 
Instead  of  actually  substituting  and  solving  numeri- 


STEAM  IN  ATOMIZATION  239 

cally,  however,  it  is  far  simpler  to  construct  a  chart 
and  pick  from  this  the  steam  consumption  for  any 
given  steam  pressure  and  pressure  difference  in  an 
orifice  placed  in  the  main. 


CALIBRATION    OF    ORIFICE    FOR    MEASUREMENT    OF    STEAM 
USED    IN    ATOMIZATION 

Previous  to  a  boiler  test  the  manometer  which  registers  the  pres- 
sure difference  at  the  faces  of  the  orifice  is  carefully  calibrated  by 
condensing-  the  steam  flow  and  weighing  the  hourly  condensate. 
These  data  when  plotted  on  a  curve  as  shown  above  enable  the 
engineer  to  quickly  ascertain  the  steam  used  in  atomization  at  any 
time  during  a  test. 

Here  then  is  presented  a  ready  and  accurate  means 
of  steam  measurement  for  atomization  purposes.  A 
diaphragm  with  an  orifice  opening  of  .5  of  a  square 
inch  in  area  is  inserted  in  the  steam  line.  On  both 
sides  of  this  diaphragm  are  drilled  holes  which  are 
tapped  for  a  ^4-inch  pipe.  The  pipes  are  then  con- 
nected to  both  legs  of  a  manometer  filled  with  mer- 
cury. A  manometer  is  nothing  more  nor  less  than  a 
U-tube  filled  with  mercury.  When  these  two  ends  are 
connected  with  pipes  of  varying  pressures,  the  mer- 
cury in  the  U-tube  will  of  course  be  raised  to  a  higher 
point  in  one  leg  of  the  U-tube  than  in  the  other.  The 
difference  in  this  height  represents  in  inches  of  mer- 


240  FUEL  OIL  AND  STEAM  ENGINEERING 

cury  the  difference  in  pressure  between  the  two  sides 
of  the  diaphragm.  If  now  a  steam  gauge  be  inserted 
in  the  steam  main  on  the  boiler  side  of  the  diaphragm, 
we  are  enabled  by  means  of  the  atmospheric  barometer 
reading  to  express  these  pressures  in  absolute  pres- 
sure units  as  set  forth  in  the  chapter  on  pressures.  On 
the  burner  side  of  the  steam  main  a  thermometer  is  in- 
serted as  shown  in  order  to  measure  the  temperature 
of  the  steam  fed  to  the  furnace,  as  this  steam  in  many 
instances  is  superheated  and  hence  the  pressure  read- 
ing does  not  indicate  the  temperature  existing. 

A  manometer  is  accurately  calibrated  prior  to  the 
test  by  allowing  the  steam  to  be  discharged  into  a 
barrel  for  a  period  of  time  under  varying  manometer 
readings.  A  curve  is  then  plotted  similar  to  the  one 
shown  in  the  illustration,  which  sets  forth  the  pounds 
of  steam  passing  per  minute  for  any  particular  mano- 
meter reading  in  inches  of  mercury.  If,  then,  read- 
ings are  taken  every  fifteen  minutes  during  the  test, 
the  testing  engineer  notes  at  such  intervals  the  steam 
that  has  passed  during  the  preceding  fifteen-minute 
period.  In  such  a  manner  the  total  quantity  of  steam 
used  in  atomization  is  ascertained. 

Thus  in  a  test  at  the  Fruitvale  Station  of  the 
Southern  Pacific  Company,  the  pressure  of  the  steam 
at  the  burner  was  found  to  be  168  pounds  per  square 
inch.  The  temperature  of  the  steam  at  the  burner  was 
440° '  F.,  which  indicated  a  superheated  condition  of 
65°  F.  The  total  steam  used  by  the  burners  for  a  ten- 
hour  test  was  found  by  the  above  means  to  be  7441 
pounds,  while  the  total  weight  of  water  fed  to  the 
boilers  proved  to  be  180,240  pounds.  Hence  the  per- 
centage of  total  water  evaporated  by  the  boilers  used 
in  atomization  is  determined  by  dividing  7441  by  180,- 
240,  which  is  4.16  per  cent. 

The  total  weight  of  oil  fired  was  14,093  pounds 
during  the  test  of  ten  hours.  Hence,  the  pounds  of 
steam  utilized  for  atomization  per  pound  of  oil  fired 
is  obtained  by  dividing  7441  by  14,093,  which  proves 
to  be  0.528  pounds. 


CHAPTER   XXIX 

THE  TAKING  OF  BOILER  TEST  DATA 

In  previous  chapters  we  have  touched  upon  all  the 
important  points  involved  in  tests  on  boiler  economy. 
These,  however,  have  been  considered  under  separate 
headings  and  of  necessity  in  a  somewhat  disconnected 
manner.  In  this  and  the  succeeding  chapters,  we  shall 
endeavor  to  link  these  items  into  a  connected  unit. 


THE   DIFFERENTIAL    DRAFT   GAGE 

In  order  to  exaggerate  the  readings  of  the  draft  in  inches  of  water, 
the  measuring  tube  rests  on  a  slope  of  ten  to  one  in  this  type  of 
instrument,  and  thus  readings  to  another  decimal  point  are  ascer- 
tained which  would  otherwise  be  impossible. 

This  chapter  will  be  concerned  with  the  gathering  of 
the  data  and  the  next  with  its  computation. 

The  Object. — ''What  can  you  do?"  applies  equally 
well  to  the  rating  of  inanimate  objects  as  well  as  to  the 
accomplishment  of  human  endeavor.  And  so  the  ob- 
ject of  boiler  testing  is  to  try  out  the  latent  steaming 
qualities  of  the  boiler  and  test  its  strength  both  for 
sudden  calls  and  for  endurance.  The  manner  in  which 
the  mechanical  design  of  the  boiler  can  withstand  such 
tests  and  especially  the  efficiency  with  which  it  can 
perform-  its  function  of  transforming  the  heat  energy 
of  the  fuel  into  energy  latent  in  the  steam  sent  forth 
from  the  boiler  are  as  a  rule  the  factors  that  either  add 
lustre  to  the  name  of  the  manufacturer  or  else  relegate 
the  type  of  steam  generator  under  test  to  the  scrap 
heap. 

241 


242 


FUEL  OIL  AND  STEAM  ENGINEERING 


BOILER  TEST  DATA  243 

The  Instructions  for  Boiler  Tests. — The  minute 
details  that  should  be  satisfied  in  order  to  secure  accu- 
rate data  wherewith  to  rate  the  boiler  and  scientifically 
set  forth  its  commercial  worth  are  elaborately  set  forth 
in  instructions  issued  by  the  American  Society  of  Me- 
chanical Engineers,  compiled  by  their  Committee  on 
Power  Tests.  In  any  case  of  actual  test,  the  steam 
engineer  should  be  provided  with  a  copy  of  these  in- 
structions, which  he  can  secure  from  the  secretary  of 
the  society  by  the  payment  of  a  small  fee. 

Since  these  instructions  require  many  pages 
wherein  to  set  forth  the  details  of  a  test,  it  cannot,  of 
course,  be  expected  that  anything  beyond  a  general 
outline  of  procedure  in  boiler  testing  be  set  forth  in 
this  article.  Still  it  has  been  the  experience  of  the 
authors  that  if  the  steam  engineer  gets  a  thorough  pic- 
ture of  the  test  details  as  a  whole  he  is  well  equipped, 
with  the  assistance  of  a  nearby  copy  of  the  detailed  in- 
structions, to  properly  understand  the  procedure. 

The  Test  for  Efficiency  Under  Normal  Rating. — 

It  has  been  seen  in  the  chapter  on  Rating  of 
Boilers  that  the  manufacturer  or  builder  rates  the  out- 
put of  the  boiler  on  the  basis  of  the  boiler  heating  sur- 
face presented  to  the  furnace  gases.  For  each  ten 
square  feet  of  boiler  surface  so  exposed  to  the  furnace 
gases,  the  boiler  is  said  to  have  one  boiler  horsepower. 
A  test  for  boiler  efficiency  under  this  normal  condi- 
tion of  operation  is  one  of  the  most  important  to  be 
ascertained  in  boiler  performance.  In  order  to  ac- 
complish this  result,  the  steam  engineer  usually  com- 
putes the  total  weight  of  water  the  boiler  would  ap- 
proximately have  to  evaporate  into  steam  per  hour 
under  the  conditions  of  entering  feed-water  tempera- 
ture, boiler  pressure,  and  quality  of  steam  generated  to 
satisfy  the  builder's  rating.  Having  made  a  careful 
estimate  of  this  quantity  he  then  proceeds  to  operate 
the  boiler  as  nearly  as  possible  to  meet  this  condition. 

Time  of  Duration  of  Test. — The  generation  of 
steam  is  maintained  as  uniformly  as  possible  over  a 
period  of  from  eight  to  ten  hours. 


244 


FUEL  OIL  AND  STEAM  ENGINEERING 


The  Beginning  and  Stopping  of  a  Test. — At  the 

beginning  of  the  test  the  level  of  water  in  the  boiler 
is  noted  on  the  water  glass  and  at  the  completion  the 
water  is  brought  to  the  same  height. 

In  the  testing  of  boilers  fired  by  fuel  oil,  the  boiler 
is  brought  up  to  and  continued  at  normal  operating 
conditions  until  the  furnace  wall  and  boiler  room"  tem- 
peratures are  at  their  normal  reading.  Then  the  test 
is  started  by  feeding  weighed  water  and  fuel  oil.  At 
the  end  of  the  test,  all  conditions  of  pressure,  tempera- 
ture and  rate  of  steam  generation  should  be  as  nearly 
as  possible  the  same  as  at  the  beginning. 


uac. 


A  Suggestion  for  a  Steam  Calorimeter  Attachment    (See  page  100) 

The  Weighing  of  the  Water.— Several  tanks  are 
placed  upon  carefully  calibrated  scales  and  all  water 
entering  the  boiler  from  the  instant  the  test  starts  to 
its  closing  point  is  carefully  weighed.  The  details  of 
the  methods  involved  in  the  weighing  of  water  have 
appeared  in  a  previous  chapter. 

The  Heat  Represented  in  the  Steam  Generated. 

• — The  temperature  of  the  entering  water  and  the  pres- 


BOILER  TEST  DATA  245 

sure  of  the  steam  generated  are  noted  at  frequent  in- 
tervals. The  quality  of  the  steam  as  to  whether  it  is 
wet  saturated,  dry  saturated,  or  superheated,  is  also 
carefully  determined  quantitatively  by  methods  out- 
lined in  previous  chapters. 

With  these  data  at  hand  the  steam  engineer  is  en- 
abled by  deductions  to  be  set  forth  in  the  chapter  on 
Heat  Balance  to  compute  the  actual  heat  energy  ab- 
sorbed by  the  entering  water  in  the  production  of 
steam. 

The  Oil,  Its  Measurement  and  Analysis. — At  the 

same  time  that  the  steam  generating  functions  of  the 
boiler  are  being  ascertained,  it  is  of  course  necessary 
to  weigh  the  fuel  oil  admitted  to  the  furnace  for  firing 
purposes  and  to  draw  frequent  samples  for  the  com- 
posite sample  to  be  used  in  ascertaining  the  heat  pro- 
ducing value  of  one  pound  of  fuel.  The  method  of 
weighing  the  oil  and  drawing  the  oil  sample  has  been 
set  forth  in  a  previous  chapter. 

Having  determined  the  calorific  value  of  one 
pound  of  fuel  by  methods  previously  described  the  to- 
tal heat  put  into  the  furnace  by  the  fuel  during  the 
test  is  computed. 

In  former  chapters  are  to  be  found  discussions 
which  fully  set  forth  the  methods  utilized  in  determin- 
ing from  the  oil  sample  its  calorific  value,  its  moisture 
content,  and  its  gravity  under  standard  conditions 
which  are  necessary  to  compute  the  total  heat  produc- 
ing value  of  the  oil  used  in  firing  the  boiler  under  test. 

The  Steam  Used  in  Atomization. — In  most  central 
station  practice  wherein  fuel  oil  is  consumed  for  heat 
generation,  the  atomization  of  the  fuel  oil  is  accom- 
plished by  blowing  into  the  furnace  through  the  oil 
burner  a  certain  quantity  of  steam  that  is  being  gener- 
ated in  the  boiler.  To  obtain  the  useful  and  economic 
quantity  of  steam  generated  by  the  boiler  we  should 
then  subtract  this  steam  used  in  atomization  from  the 
total  steam  generated  in  the  test.  A  practical  method 
of  obtaining  experimentally  the  steam  used  in  atomi- 
zation has  been  described  in  a  previous  chapter. 


246  FUEL  OIL  AND  STEAM  ENGINEERING 

The  Boiler  Efficiency. — Having  thus  obtained  the 
net  heat  absorbed  by  the  boiler  under  test  and  also  the 
heat  given  out  by  the  fuel  oil  sprayed  into  the  furnace, 
the  ratio  of  the  former  to  the  latter  gives  us  the  effi- 
ciency of  the  boiler  as  set  forth  in  the  chapter  on  Heat 
Balance. 

In  central  station  practice  on  the  Pacific  Coast  the 
gross  boiler  efficiency  in  the  best  installations  ranges 
from  81  to  83  per  cent  under  test  conditions.  The 
atomization  of  the  steam  lowers  this  efficiency  by 
about  2  per  cent,  thus  making  the  best  net  boiler  effi- 
ciencies range  between  79  and  81  per  cent. 

The  Overload  Test. — The  sudden  demands  for 
power  during  certain  hours  of  the  day  make  an  elas- 
ticity in  boiler  steaming  qualities  absolutely  impera- 
tive. Otherwise,  a  great  additional  expense  would  be 
involved  in  the  cost  and  installation  of  additional 
steaming  units.  Hence  the  overload  steaming 
qualities  of  a  boiler  are  of  utmost  importance,  especial- 
ly in  central  station  or  steam  auxiliary  practice. 

As  an  instance  of  performance  of  a  boiler  under 
overload  conditions  on  the  Pacific  Coast,  an  authentic 
case  is  on  record  where  a  boiler  of  773  rated  horse- 
power developed  an  overload  of  75.7  per  cent  for  5 
hours  and  still  maintained  a  gross  efficiency  of  80.62 
per  cent. 

The  Quick  Steaming  Test. — In  other  instances 
the  ability  of  a  boiler  to  hastily  get  into  action  is  of 
prime  importance.  This  is  especially  true  in  cases 
where  boilers  are  held  in  readiness  for  pumping  sta- 
tion operation  for  fire  protection.  In  San  Francisco, 
California,  for  instance,  is  located  a  high-pressure 
water  system  whereby  pumps  stand  eternally  ready 
to  deliver  12,000  gallons  of  water  per  minute  to  a* 
height  of  700  feet  should  disaster  by  fire  ever  again 
visit  that  municipality.  The  boilers  that  operate  the 
pumping  station  have  by  test  demonstrated  that  full 
boiler  pressure  and  steaming  conditions  can  be  ac- 
compl:shed  in  less  than  thirty  minutes  time. 

Again,  other  features  of  test  are  under  special 
cases  desirable  to  attain.  But  the  two  most  important 


BOILER  TEST  DATA  247 

tests  are  those  of  ascertaining  the  conversion  ratio  of 
heat  represented  in  the  steam  to  the  heat  supplied  by 
the  furnace  under  normal  conditions  of  operation  and 
under  certain  definite  overload  guarantees — in  a  word, 
the  ascertaining  of  boiler  efficiency  for  normal  rating 
and  for  conditions  of  overload. 

Observations  Necessary. — A  complete  tabulated 
list  for  final  test  computation  is  set  forth  in  the  book 
of  instructions  previously  mentioned  as  approved  or 
advised  by  the  American  Society  of  Mechanical  En- 
gineers. Let  us  now  look  into  some  of  the  details 
necessary  to  obtain  this  recorded  data. 

In  the  first  place,  one  should  note  on  a  log  sheet 
the  general  observations  such  as  date  of  test,  duration 
of  test,  type  of  oil  burner,  make  of  oil  burner,  number 
of  burners  used,  and  with  this  information  should  be 
compiled  sufficient  physical  dimensions  of  the  boiler 
to  enable  one  to  compute  the  builder's  rating  both  for 
the  boiler  and  for  the  superheater.  An  illustration  of 
this  computation  was  set  forth  under  the  chapter  on 
Rating  of  Boilers. 

During  the  test  period,  observations  are  usually 
taken  every  fifteen  minutes,  simultaneously  if  possible. 

Pressure  Readings. — The  pressure  of  the  atmos- 
phere is  read  in  inches  of  mercury  and  the  steam  gauge 
readings  of  the  boiler  and  superheater  having  been 
duly  calibrated  or  corrected  for  mechanical  inaccur- 
acies, are  then  reduced  to  absoluute  pressure  readings 
as  set  forth  in  the  chapter  on  pressures. 

The  pressure  of  the  oil  under  which  it  is  forced 
into  the  furnace  is  also  usually  noted,  although  it  has 
no  bearing  on  data  computation. 

The  pressure  of  the  draft  at  various  parts  of  the 
ash  pit,  furnace,  breeching,  and  chimney  are  also  noted 
by  means  of  a  multiple  cock  arrangement  which  was 
shown  in  the  chapter  on  pressures.  This  arrangement 
makes  possible  the  quick  ascertaining  of  various  draft 
readings  by  means  of  one  instrument. 

The  pressure  of  the  saturated  steam  and  also  that 
of  the  superheated  steam  is  ascertained  by  inserting 


248  FUEL  OIL  AND  STEAM  ENGINEERING 

carefully  calibrated  steam  gages,  the  one  in  the  satu- 
rated steam  compartment  and  the  other  in  the  super- 
heater compartment.  These  pressures  are  then  con- 
verted into  absolute  pressure  readings  by  correcting 
for  atmospheric  pressure  as  set  forth  in  the  chapter  on 
pressures. 

Temperature  Readings. — A  thermometer  is  usu- 
ally located  in  the  atmosphere  without  to  ascertain 
general  external  temperature  conditions  of  the  day. 
One  is  also  placed  in  the  boiler  room  to  ascertain  the 
temperature  of  the  entering  air  passing  into  the  fur- 
nace. 

To  ascertain  the  temperature  of  entering  feed  wa- 
ter and  fuel  oil,  thermometer  wrells  with  thermometers 
are  also  installed  at  nearby  points  of  entrance. 

It  is  often  desirable  to  ascertain  the  temperature 
of  the  furnace  gases  at  various  points  in  their  journey. 
To  accomplish  this  thermo-couples  are  installed  at  the 
points  desired  previous  to  the  firing  of  the  boilers  and 
during  the  test  an  electrical  pyrometer  is  advised,  espe- 
cialy  if  other  high  temperatures  are  to  be  taken  in 
various  points  of  flue  gas  passage. 

The  Flue  Gas  Analysis. — Simultaneously  with  the 
taking  of  the  temperatures,  pressure  and  other  read- 
ings of  the  test,  the  flue  gas  anaylsis  is  ascertained  at 
frequent  intervals.  The  detailed  method  of  taking  these 
data  has  been  fully  set  forth  in  previous  chapters  and 
methods  of  computation  of  combustion  data  explained. 
The  Heat  Balance  will  be  set  forth  in  full  in  a  later 
chapter. 

The  Test  as  a  Whole. — The  reader  has  now  be- 
fore him  the  taking  of  the  test  as  a  whole.  At  this 
point  he  should  carefully  review  all  the  previous  chap- 
ters alluded  to  in  this  discussion  so  as  to  wreld  into  a 
solid  chain  the  links  that  go  to  make  up  the  boiler 
test  in  fuel  oil  practice. 

Having  thus  in  mind  a  complete  idea  of  the  vari- 
ous details  involved  in  the  taking  of  the  boiler  test 
data,  we  are  now  in  position  to  link  together  the  com- 
puted data  involved  in  formulating  the  engineer's  re- 
port of  the  economic  results  of  the  test. 


CHAPTER   XXX 

PRELIMINARY    TABULATION    AND    CALCU- 
LATION OF  TEST  DATA 

The  systematic  construction  of  a  log  sheet  that 
will  show  in  the  minutest  detail  every  incident  in  the 
progress  of  the  boiler  test  is  of  prime  importance.  It 
is  far  better  to  overdo  than  to  underdo  in  the  gather- 
ing of  detail  data  of  this  kind.  The  notation  of  re- 
marks from  time  to  time  upon  the  log  sheet  concern- 
ing relevant  observations  during  the  progress  of  the 
test  is  of  much  service  to  the  engineer  when  he  final- 
ly comes  to  decide  fine  points  in  economic  boiler  per- 
formance. 

No  straight  and  narrow  schedule  or  log  sheet  can 
be  set  forth  to  meet  all  types  of  boiler  test.  Each  par- 
ticular test  as  a  rule  involves  its  own  particular  tabu- 
lation. Let  us,  however,  consider  a  series  of  tabula- 
tation  sheets  for  boiler  tests  in  which  oil  is  used  as 
a  fuel.  The  suggestions  that  will  be  set  forth  illustrate 
a  carefully  evolutionized  scheme  of  tabulation  for  such 
data  that  may  be  well  followed  in  guiding  one  in  the 
construction  of  his  own  individual  log  form  should  oc- 
casion arise. 

The  Log  Sheet  for  Weighing  the  Water.— In  the 
previous  chapter  wre  have  seen  that  the  water  is 
brought  to  a  definite  height  in  the  supply  tank  the  in- 
stant of  starting  the  test.  Above  this  supply  tank  are 
located  standardized  scales  upon  which  the  water  is 
weighed  before  emptying  into  the  supply  tank  below. 
As  a  rule,  at  the  closing  of  each  hourly  period,  water 
readings  are  computed  in  order  that  the  engineer  may 
get  a  preliminary  idea  of  the  progress  of  the  test. 
Blank  sheets  are  given  each  water  weigher,  one  to  be 
used  for  each  hourly  period.  Each  sheet  sets  forth 
general  information  indicating  the  kind  of  boiler  un- 

249 


250 


FUEL  OIL  AND  STEAM  ENGINEERING 


der  test,  the  date  of  test,  the  name  of  the  observer,  and 
the  particular  tank  at  which  each  is  stationed.  A  col- 
umn is  devoted  to  the  number  of  the  scale  reading,  a 
second  to  the  gross  weight  of  the  water  and  tank  be- 
fore emptying  into  the  tank  below,  the  tare  to  be  sub- 
tracted from  the  gross  weight,  which  is  the  weight 
of  the  upper  tank  after  the  water  is  emptied  into  the 
tank  below,  and  a  fourth  column  setting  forth  the  net 
weight  or  difference  of  the  two  preceding  columns. 
This  sheet  will  have  somewhat  the  following  appear- 


ance : 


Log  Sheet  for  later  i*ed  JC£  Boiler. 


Kind  01  Dollar  

Method  of 'Starting  Test 

Date 

Obs errors  at  Scales  for  Mater 


Heading 

Time 

tiro  3  a 

Tare 

Uet 

Temp.  of 
Waoer 

Hemarka 

1. 

B. 

3. 

4. 

R< 

6. 

Y. 

a. 

2ot«l 


Signature: 


By  using  the  type  of  log  sheet  above  indicated, 
it  is  evident  that  the  engineer  has  a  check  on  his  water 
computation,  for  in  the  line  marked  "total"  the  footing 
for  the  gross  weight  should  exactly  equal  that  for  the 
sum  of  the  tare  weight  and  the  net  weight.  A  place 
is  also  given  for  a  signature  to  be  appended  by  the  one 
responsible  for  the  weight  notation. 

Log  Sheet  for  the  Fuel  Oil  Fed  to  Furnace. — 
Simultaneously  with  the  weighing  of  the  water,  a  sim- 
ilar log  sheet  is  kept  by  another  set  of  observers  setting 
forth  the  weight  of  fuel  oil  fed  to  the  furnace.  As  the 
weighing  proceeds,  a  periodic  sample  is  taken  to  make 


PRELIMINARY  TABULATION 


251 


up  a  composite  sample  for  the  determination  of  the 
calorific  value  of  the  oil  as  set  forth  in  the  preceding 
chapter.  The  log  sheet  for  the  oil  is  quite  similar  to 
that  used  for  the  water  and  should  be  footed  up  at  the 
end  of  each  hourly  period  so  that  the  engineer  may 
have  some  definite  idea  of  preliminary  economic  re- 
sults. A  suggestion  for  this  log  sheet  is  as  follows : 


Log  aneet  for  uil  Pad  TA_  ffurnaee. 


frype   and  .Location  of  Boiler 

Type   of  Burner  

Type  of  i'urnaoe 

Date 

Observers  at  Scales  for  Oil 


loading 

line 

Gross 

Tare 

Het 

Temp.  of 
Oil 

.Remarks 

1. 

2. 

3. 

4. 

0. 

0. 

7. 

w. 

i'o-cal 

Other  Data  to  be  Taken. — The  tabulation  of  data 
to  determine  the  steam  used  for  atomization  and  the 
analysis  of  the  flue  gases  require  special  treatment,  de- 
pending upon  the  particular  method  decided  upon  by 
the  engineer  to  ascertain  these  factors.  Previous 
chapters  have  already  set  forth  in  detail  suggestions 
for  the  ascertaining  of  these  quantities,  and  the  reader 
is  now  advised  to  re-read  them  in  order  to  correlate 
in  his  mind,  as  it  were,  all  the  data  that  must  be  taken 
in  order  to  ascertain  the  economic  performance  of  the 
modern  boiler  utilizing  crude  petroleum  as  a  fuel. 

The  General  Log  Sheet. — In  addition  to  the  two 
log  sheets  just  described,  a  general  log  sheet  is  neces- 
sary upon  which  to  note  the  temperatures,  pressures, 
flue  gas  analysis  and  other  information  desired. 


252 


FUEL  OIL  AND  STEAM  ENGINEERING 


eaoa-o 


880,19 


3aTiaq.ua 


ITO 


jo'dnrai 


'4.3:  9 


3ui.iaq.u9 


JO 


j:o  90JOI 


oregls 


9UITJ, 


PRELIMINARY  TABULATION 


253 


THE   GRAPHIC    LOG   SHEET   FOR    FUEL   OIL  TESTS 
During   the   progress   of  a   test   a   graphic   plot   most   conveniently 
sets  forth  the  behavior  of  the   variables   under  observation.     The 
above  shows  a  typical  graphic  log  sheet  and  its  method  of  construc- 
tion for  fuel  oil  tests. 


254  FUEL  OIL  AND  STEAM  ENGINEERING 

Here  is  an  illustration  of  a  suggestion  for  such  a 
log  sheet.  At  the  completion  of  the  test  an  average 
is  easily  obtained  for  the  various  readings  by  footing 
up  the  total  and  dividing  by  the  number  of  readings 
noted.  The  columns  for  the  water  fed  to  the  boiler 
and  the  oil  fed  to  the  furnace  are  footed  and  as  in  the 
hourly  sheets  previously  described,  the  totals  from 
these  sheets  which  are  noted  on  this  general  log  sheet 
should  now  check  —  that  is,  the  total  gross  should 
equal  the  sum  of  the  total  tare  and  total  net  columns. 
The  reader  is  to  bear  in  mind  that  the  actual  notations 
to  be  made  in  any  particular  test  are  not  all  set  down 
in  this  general  log  sheet  suggestion.  For  the  infor- 
mation desired  and  the  purpose  of  the  test  must  in 
each  given  case  determine  these  factors.  The  sheet 
will,  however,  serve  as  a  general  guide  for  such  mat- 
ters. 

The  Plotting  of  Test  Data — As  the  test  proceeds 
hour  by  hour,  it  is  very  instructive  and  helpful  to 
keep  a  diagramatic  log  sheet  also.  By  this  means  a 
glance  will  often  reveal  certain  irregularities  that  may 
be  righted  at  their  incipiency.  Such  a  log  sheet  is 
shown  in  the  illustration  and  by  reference  to  it  the 
reader  will  observe  how  the  history  of  a  test  may  be 
simply  and  clearly  set  forth. 


CHAPTER  XXXI 

THE  HEAT  BALANCE   AND    BOILER 
EFFICIENCY 

The  steaming  qualities  of  a  boiler  are  best  set 
forth  by  measuring  its  so-called  efficiency.  The  effi- 
ciency of  a  boiler  is  the  relationship  between  the  heat 
absorbed  per  pound  of  fuel  fired  and  the  calorific  value 
of  one  pound  of  fuel.  Thus  although  each  pound  of 
fuel  consumed  in  steam  production  is  found  to  have  a 
calorific  value  of  19,450  B.  t.  u.  in  the  numerical  illus- 
tration for  this  chapter,  that  portion  alone  of  this  heat 
which  is  actually  represented  in  the  steam  itself  is  of 
economic  value. 

In  the  illustrative  test  which  is  made  use  of 
throughout  this  chapter,  it  will  be  found  that  of  this 
19,450  B.  t.  u.  represented  in  each  pound  of  oil  only 
14,076.56  go  toward  power  generation.  It  is  then  use- 
ful and  instructive  to  analyze  the  losses  in  a  boiler  and 
see  through  what  channels  this  heat  has  been  dissi- 
pated. The  major  portion  of  these  losses  may  be  easily 
computed  by  means  of  data  taken  in  the  test.  Those 
which  cannot  be  mathematically  computed  are  thrown 
under  the  column  entitled  "Stray  Losses,"  and  are 
made  to  represent  such  an  amount  that  the  total  losses 
together  with  the  useful  heat  generated  in  the  boiler 
represent  the  heat  from  one  pound  of  fuel. 

Let  us  then  examine  the  various  channels  of  heat 
transfer  going  on  in  the  boiler  and  see  how  the  details 
of  the  heat  balance  are  set  forth.  In  this  discussion  H0 
will  represent  the  calorific  value  of  one  pound  of  fuel 
oil  under  test. 

(a)  a.  The  total  heat  absorbed  by  the  boiler.  As 
has  been  previously  shown,  the  equivalent  evaporation 
of  a  boiler  per  pound  of  oil  represents  the  number  of 
pounds  of  water  which  would  be  evaporated  into  steam 

255 


256  FUEL  OIL  AND  STEAM  ENGINEERING 

per  pound  of  oil  if  the  water  was  at  212°  F.  and  under 
atmospheric  pressure,  and  this  water  then  converted 
into  dry  saturated  steam  at  the  same  temperature  and 
pressure.  It  is  self-evident  then  that  the  total  heat  ab- 
sorbed by  the  boiler  for  each  pound  of  oil  burned  in  the 
furnace  is  equal  to  the  equivalent  evaporation  multi- 
plied by  the  heat  necessary  to  convert  one  pound  of 
water  into  steam  under  conditions  just  mentioned. 
This  quantity  of  heat  has  been  found  by  Marks  and 
Davis  to  be  970.4  B.  t.  u.,  as  set  forth  in  previous  dis- 
cussions. Representing  this  in  a  formula  the  total 
heat  Ht  absorbed  by  the  boiler  per  pound  of  fuel  is 

Ht  =  =  Me  X  Lc (1) 

in  which  Ht  is  the  total  heat  absorbed  by  the. boiler 
per  pound  of  dry  fuel,  .Me  the  equivalent  evaporation 
per  pound  of  oil,  and  Le  the  latent  heat  of  evaporation 
at  212°  F.,  which  is  970.4  B.  t.  u.  Hence,  if  the  equiva- 
lent evaporation  of  a  boiler  is  found  by  test  to  be  28,- 
225  pounds  of  water  per  hour,  and  if  the  measurement 
of  oil  shows  that  1872  pounds  of  oil  have  been  con- 
sumed 

28225 

Me    =- 

1872 

28225 

/.  Ht  =  -         -  X  970.4  =  14639 
1872 

b.     Heat  absorbed  by  boiler  for  atomizat;on. 

In  ordinary  practice  of  fuel  oil  consumption,  there  are 
three  methods  of  atomization  employed.  In  the  larger 
power  plants  the  use  of  steam  for  atomization  pur- 
poses, or  in  other  words,  the  diverting  of  steam  from 
the  boiler  into  the  furnace  in  order  to  atomize  the  oils, 
seems  to  have  by  far  the  preference.  It  is  proposed 
to  alter  the  rules  of  the  American  Society  of  Mechani- 
cal Engineers  so  that  the  heat  represented  by  the 
s'leam  used  in  atomization  must  be  subtracted  from  the 
total  heat  absorbed  by  the  boiler  in  order  to  compute 


HEAT  BALANCE  257 

the  net  evaporative  power  of  the  boiler.  Hence  to 
make  this  computation  we  must  know  the  number  of 
pounds  of  steam  used  in  atomization  per  pound  of  oil 
burned.  Methods  of  arriving  at  this  result  have  been 
described  in  a  previous  chapter. 

Calling  Ms  the  pounds  of  steam  used  in  atomiza- 
tion per  pound  of  fuel  burned,  Hs  the  total  heat  per 
pound  of  steam  so  used,  and  h1  the  heat  in  the  entering 
feed  water,  and  Ha  the  heat  absorbed  by  the  boiler  per 
pound  of  fuel  in  atomizing  the  oil,  it  is  evident  that 

Ha==M.(H.  — hO (2) 

Thus  it  has  been  found  in  the  test  under  descrip- 
tion that  .530  pounds  of  steam  were  utilized  in  atomi- 
zation per  pound  of  oil.  Saturated  steam  at  a  temper- 
ature of  381.9°  was  used.  From  the  steam  tables  such 
steam  is  found  to  have  a  total  heat  of  1198.08  B.  t.  u. 
The  entering  feed  water  was  at  a  temperature  of  169.1° 
F.  and  has  a  heat  of  liquid  amounting  to  136.87  B.  t.  u. 
We  find  by  substitution  that  the  heat  absorbed  in 
atomizing  the  oil  is  computed  as  follows : 

Ha  ==  .530  (1198.98  —  136.87)  ==  562.44  B.  t.  u. 

c.  Net  heat  absorbed  by  boiler  for  power  gen- 
eration. Since  then  the  heat  utilized  in  atomization 
must  be  subtracted  from  the  total  heat  abso-bed  by  the 
boiler,  to  ascertain  the  net  heat  Hn  absorbed  by  the 
boiler  for  power  generation,  we  have  the  following  for- 
mula : 

Hn=  Ht  — Ha    .". (3) 

.'.Hn  =  14639  — 562.44  =14076.56  B.t.u. 

(b)     Loss  due  to  water  in  the  fuel. 

All  fuels  contain  a  certain  amount  of  moisture.  It 
is  evident  that  since  it  requires  considerable  heat  to 
convert  this  moisture  into  steam  and  then  to  send  it 
forth  from  the  chimney  in  a  superheated  condition,  a 
definite  loss  is  thereby  sustained  in  boiler  operation. 
This  moisture  must  first  be  raised  to  212°  F.,  then  con- 
verted into  steam,  and  then  heated  to  the  temperature 
of  the  outgoing  chimney  gases.  If  we  let  Mw  be  the 
proportion  by  weight  of  moisture  in  the  one  pound  of 
fuel,  t0  the  temperature  of  the  oil  entering  the  burner, 


258  FUEL  OIL  AND  STEAM  ENGINEERING 

ts  the  temperature  of  the  escaping  gases,  and  Hm  the 
loss  due  to  moisture  in  the  fuel  per  pound  of  fuel 
burned,  we  may  write  at  once  an  equation  represent- 
ing this  loss. 

Thus 
Hm  ==  Mw  [212  —  t0  +  970.4  +  .47  (tg  —  212)  ] ....  (4) 

The  reasons  for  this  formula  are  seen  by  inspec- 
tion. To  raise  each  pound  of  moisture  from  t0  to  212° 
F.  would  require  as  many  B.  t.  u.  as  the  raise  in  tern- 
perature,  in  other  words  (212 — 10)  B.  t.  u.  Again,  to 
evaporate  each  pound  would  require  970.4  B.  t.  u.,  and 
as  .47  of  a  B.t.u.  are  required  to  superheat  one  pound  of 
steam  one  degree  in  temperature  at  atmospheric  pres- 
sure, each  pound  of  steam  superheated  to  the  temper- 
atur  of  the  outgoing  chimney  gases  would  require  .47 
(tg  —  212)  B.  t.  u.  Therefore,  the  total  heat  required 
for  Mw  pounds  would  be  as  indicated  in  the  formula 
above  by  summing  up  these  separate  components. 

Thus  in  the  test  under  consideration,  let  us  assume 
that  the  fuel  contains  1  per  cent  of  moisture ;  that  its 
entering  temperature  is  96°  F.,  and  that  the  tempera- 
ture of  the  escaping  gases  is  400°  F.     Hence 
Hm  =  .01  [212  —  96  +  970.4  +  .47  (400—212)  ]  = 
11.67  B.  t.  u. 

(c)  Loss  due  to  water  formed  by  burning  hy- 
drogen. 

In  the  chapter  on  chimney  gas  analysis,  it  was  seen 
that  the  Orsat  Apparatus  is  so  constructed  that  the 
vapor  or  superheated  steam  formed  by  the  burning  of 
the  hydrogen  content  in  the  fuel  is  condensed  into  wa- 
ter upon  entering  the  burette ;  hence  the  Orsat  an- 
alysis indicates  only  dry  flue  gases  and  takes  no  ac- 
count of  the  percentage  of  steam  actually  present  in 
these  gases.  It  is  seen  then  that  the  moisture  formed 
by  the  burning  of  hydrogen  mu'st  also  create  a  loss  as 
it  journeys  upward  through  the  boiler.  Assuming  H^ 
to  be  the  heat  lost  due  to  the  moisture  formed  by  the, 
burning  of  hydrogen  by  following  .identically  similar 
processes  of  reasoning  just  employed  in  the  considera- 
tions of  the  loss  due  to  the  moisture  in  the  fuel,  ,we. 


HEAT  BALANCE  259 

find  that  each  pound  of  moisture  formed  by  the  burn- 
'ing  of  hydrogen  requires 

[212  —  t0  +  970.4  +  .47  (tg  —  212)]  B.  t.  u. 

From  the  principles  of  chemistry  each  pound  of 
hydrogen  combines  with  8  pounds  of  oxygen,  there- 
by forming  9  pounds  of  water  or  steam.  This  rela- 
tionship gives  us  a  ready  means  of  computing  the 
weight  of  water  vapor  formed  by  the  burning  of  hydro- 
gen, although  the  Orsat  analysis  failed  to  do  so.  As- 
suming Mh  to  be  the  proportion  by  weight  of  hydrogen 
per  pound  of  fuel  oil  burned,  we  have 

Hh  =  9Mh  [212  —  t0  +  970.4  +  .47  (tg  —  212)  ] .  .  (5) 

By  referring  to  the  test  data,  w7e  find  that  the  fuel 
analysis  show's  .11  pounds  of  hydrogen  per  pound  of 
fuel,  that  the  temperature  of  entering  air  is  84°  and  the 
temperature  of  the  escaping  gases  400°,  therefore 

Hh  =  9X-H  [212—84  +  970.4+  .47  (400—212)]  = 
1166.97  B.  t.  u. 

(d)     Loss  due  to  heat  carried  away  by  dry  gases. 

From  the  Orsat  analysis,  as  wras  seen  in  Chapter 
XXV  on  the  Computation  of  Combustion  Data,  the 
pounds  of  dry  gas  passing  up  the  chimney  per  pound 
of  fuel  burned  may  be  easily  computed  by  means  of 
.several  ^different  formulas.  It  is  found  by  experiment 
that  it  requires  .24  B.  t.  u.  to  raise  one  pound  of  chim- 
ney gas  one  degree  in  temperature.  Hence  if  Mg  be 
the  pounds  of  dry  chimney  gas  per  pound  of  fuel,  the 
total  heat  wasted  Hs  in  raising  the  temperature  of 
these  dry  gases  is  seen  to  be 

Hg  =  .24  (tg  —  ta)  MB  (6) 

In  this  particular  instance,  let  us  assume  that  by 
the  application  of  our  formula  we  find  that  19.83 
pounds  of  dry  chimney  gas  are  formed  per  pound  of 
fuel  burned ;  that  the  temperature  of  the  entering  air 
is  84.1°,  and  that  of  the  outgoing  chimney  gases  400°. 
Hence 

Hg  =  .24  (400  —  84)  19.83  =  1503.91  B.  t.  u. 


260  FUEL  OIL  AND  STEAM  ENGINEERING 

(e)     Loss  due  to  carbon  monoxide. 

In  the  burning  of  every  pound  of  carbon  to  carbon 
dioxide,  14,600  B.  t.  u.  are  liberated.  When  the  car- 
bon is  not  completely  burned  but  passes  up  the  chim- 
ney in  the  form  of  carbon  monoxide  only  4450  B.  t.  u. 
per  pound  of  carbon  so  burned  are  liberated.  Hence 
whenever  carbon  monoxide  appears  in  the  gas  analysis 
it  is  evident  that  a  definite  loss  is  being  sustained  due 
to  this  incomplete  combustion  of  the  carbon. 

For  every  pound  of  carbon  which  passes  up  the 
chimney  as  carbon  monoxide,  a  net  loss  of  10,150  B. 
t.  u.  are  thus  uselessly  thrown  away.  Let  us  assume 
that  one  pound  of  carbon  volumetrically  produces  Vt 
units  by  volume  of  carbon  dioxide  and  V3  units  by 
volume  of  carbon  monoxide.  If  this  is  true  it  is  evi- 


dent  that  in  every  pound  of  carbon  so  burned  - 

V.  +  V, 

pounds  are  converted  into  carbon  monoxide,  which 
represents  a  loss  of  10,150  B.  t.  u.  per  pound.  Hence  if 
there  are  C  units  of  carbon  by  weight  in  each  pound 
of  the  fuel,  the  formula  to  be  applied  to  ascertain  the 
loss  due  to  incomplete  combustion  Hc  is 

V3     • 

Hc  =  C—  -  X  10,150  .................  (T, 

Vt  +  V3 

In  the  particular  case  cited  above  the  fuel  has  .86 
proportions  by  weight  of  carbon  and  .01  proportions 
by  volume  go  out  of  the  chimney  in  the  form  of  car- 
bon monoxide  and  .0979  proportions  by  volume  in  the 
form  of  carbon  dioxide.  Then  the  total  loss  is  evi- 
dently 

10150  X-01 
Hc  =  .86  -  -  =  801.82  B.  t.  u. 

.0979  +  .01 

(f)   a.  Loss  due  to  evaporating  steam  for  atom- 
ization. 

By  referring  back  to  (a)  b  in  this  discussion,  we 
find  that  the  loss  due  to  evaporating  steam  used  in 
atomization  is  represented  by  the  formula 


HEAT  BALANCE  261 

Ha  =  Ms  (Hs  — hj  (8) 

and  in  the  particular  instance  in  question  it  is  56.44 
B.  t.  u.  per  pound  of  fuel  burned.  Where  the  steam 
used  in  atomization  is  brought  from  an  outside  source, 
it  would,  of  course,  be  necessary  to  neglect  the  correc- 
tion made  under  (a)  b,  although  the  quantity  under 
this  heading  must  still  be  taken  into  account. 

b.  Loss   due  to  superheating  steam  used  for 
atomization. 

If  the  steam  has  been  injected  into  the  furnace  in 
atomization,  it  is  clearly  evident  that  for  every  pound 
so  injected,  .47  of  a  B.  t.  u.  are  required  in  superheat- 
ing it  to  the  temperature  of  the  outgoing  chimney 
gases.  Hence  the  loss  so  sustained  is  seen  at  once  to 
be  computed  from  the  formula: 

Hsa  =  .47  Ms  (tg  —  tB) (9) 

in  which  Hsa  is  the  loss  due  to  superheating  steam  due 
to  atomization  per  pound  of  fuel  burned  ;  Ms  is  the  pro- 
portion by  weight  of  steam  used  in  atomization  per 
pound  of  oil;  tg  the  temperature  of  escaping  flue  gas; 
and  ts  the  temperature  of  steam  used  in  atomization. 

Since  we  have  found  that  .53  pound  of  steam  were 
used  per  pound  of  oil  in  atomization  and  the  temper- 
ature of  the  outgoing  chimney  gases  was  400°,  and 
that  of  the  inlet  temperature  of  the  steam  381.9°,  we 
see  at  once  that 

Hsa  =  .47  X  -53  (400—381.9)  =  4.51  B.  t.  u.  per 
pound  of  oil  burned. 

c.  Total  loss  in  atomization.   If  now  the  steam 
supply  in  atomization  is  taken  from  the  boiler  under 
test,  or  even  brought  from  a  separate  supply,  it  is  clear 
that  the  total  loss  so  sustained  is  the  sum  of  Ha  and 
Hsa.    Hence  the  total  loss  Hta  in  atomization  is 

Hta  =  Ha+Hsa (10) 

In  the  case  at  issue  then, 

Hta  =  562.44  +  4.51  =  566.95  B.  t.  u. 


262  FUEL  OIL  AND  STEAM  ENGINEERING 

(g)    Loss  due  to  moisture  in  entering  air. 

All  air  drawn  into  a  furnace  holds  in  suspension 
a  certain  amount  of  moisture.  In  previous  instances 
of  moisture  entering  the  flue  gas  it  is  seen  that  a  loss  is 
sustained  in  superheating  this  moisture  content  to  the 
temperature  of  the  outgoing  chimney  gases.  Let  Ma 
be  the  pounds  of  air  that  enter  the  furnace  per  pound 
of  fuel  burned,  and  let  K  be  the  proportion  by  weight 
of  moisture  in  this  entering  air,  then  the  loss  in  heat 
units  Hma  due  to  this  moisture  may  be  expressed  at 
once  by  the  formula 

HmB  =  .47  MaK  (tg  — t.) (11) 

In  the  illustration  cited  in  this  case  it  was  found 
that  there  were  22.82  pounds  of  chimney  gas  formed, 
which  means  that  21.82  pounds  of  air  were  drawrn 
into  the  furnace  to  burn  one  pound  of  fuel  oil ;  that  the 
entering  moisture  represented  .75  per  cent  of  the  en- 
tering air  which  found  its  \vay  into  the  furnace  at  a 
temperature  of  84°  and  escaped  from  the  chimney  at 
a  temperature  of  400°. 

Therefore 

Hma  ==  .47  (21.82)  X  -0075  (400—84)  =  23.18  B.t.u. 

(h)    Stray  losses. 

In  order  to  make  a  perfect  balance  between  all  of 
of  the  various  factors  entering  a  heat  balance,  the 
residual  heat  of  each  pound  of  oil  not  otherwise  ac- 
counted for  is  thrown  into  a  column  headed  "Stray 
Losses."  It  is  clearly  evident  that  this  loss  is  equal  to 
the  calorific  value  of  the  fuel  per  pound  less  the  sum  of 
all  the  heat  accounted  for  in  the  various  columns  cited 
above.  Hence  if  Hs  represents  the  stray  losses  per 
pound  of  fuel,  and  H0  the  calorific  value  of  one  pound 
of  fuel  oil  under  test,  we  may  write  the  formula  as 
follows : 

H8=H0—  (Hn+Hm+Hh+Hs+Hc+Hta+Hma)  ...  (12) 

and  in  the  case  at  issue  by  summarizing  the  columns 
we  find  this  to  be  18151.06  B.  t.  u. 

/.  Hs  ==  19450  —  18151.06  =  1298.94  B.  t.  u. 


HEAT  BALANCE  263 

(i)     Total  Calorific  Value  or  Summary. 

We  are  now  in  a  position  to  summarize  the  com- 
plete heat  balance.  The  various  items  just  discussed 
will  be  seen  to  be  represented  both  in  B.  t.  u.  per  pound 
and  in  percentages,  as  follows : 

Summary  for    Heat    Balance 

Heat 

Losses Avail- 
in  B.  t.  u.     %        able 

Total  B.  t.  u.  in  1  pound  water  free  oil..  19450 

(a)  a.  In     total     heat     absorbed     by 

boiler 14639.00 

b.  Heat    absorbed    for    atomiza- 

tion  .  562.44 


c.  Net  heat  absorbed  for  power 14076.56       72.37 

(b)  Loss  due  to  moisture  in  fuel 11.67  .06 

(c)  Loss  due  to  moisture  of  burning-  H 1166.97         6.00 

(d)  Loss  due  to  heat  carried  away  by  gases     1503.91         7.73 

(e)  Loss  due  to  incomplete  combustion  of  C.       801.82         4.12 

(f)  a.  Loss    due     to    evaporation     of 

steam    for   atomization 562.44 

b.  Loss   due   to    superheating    of 

steam  by  atomization 4.51 


c.   Total  loss  due  to  atomization 566.95         2.92 

(g)  Loss  due  to  moisture  of  entering  air....         23.18  .12 

(h)   Stray  losses    1298.94         6.68 


19450.00     100.00     19450 

The  Net  Boiler  Efficiency. — In  fuel  oil  central  sta- 
tion practice,  due  to  the  fact  that  a  portion  of  the 
steam  generated  in  the  boiler  is  used  for  atomization, 
we  need  further  definition  for  true  boiler  efficiency 
than  the  notation  set  forth  in  the  Rules  for  Boiler  Tests 
advised  by  the  Power  Test  Committee  of  the  Ameri- 
can Society  of  Mechanical  Engineers.  Further  com- 
ment on  this  point  will  be  made  in  the  next  chapter. 
Suffice  it  to  say  here,  howrever,  that  the  net  boiler  ef- 
ficiency Bne  for  the  boiler  wrill  be  considered  as  that 
resulting  from  taking  the  ratio  of  the  heat  Hn  repre- 
sented in  the  useful  steam  evaporated  by  the  boiler 
per  pound  of  oil  fired  to  the  total  heat  H0  given  out 
by  each  pound  of  oil  burned.  Thus 

Hn 

Bne'  =  -   (13) 

H0 

In  the  data  set  forth  in  the  heat  balance  just  com- 
puted we  find  then  that 


264  FUEL  OIL  AND  STEAM  ENGINEERED 

14076.56 

Bne  =  -  -  =  72.37% 

19450 

The  Boiler  Efficiency  as  a  Steaming  Mechan- 
ism. —  In  case,  however,  it  is  desired  to  ascertain  the 
boiler  efficiency  Be  as  a  steaming  mechanism,  it  would 
then  of  course  be  proper  to  compute  this  boiler  effi- 
ciency Be  by  taking  the  ratio  of  the  total  heat  Ht  ab- 
sorbed by  the  steam  for  each  pound  of  oil  fired  to  the 
total  heat  H0  actually  given  out  by  each  pound  of  fuel 
oil  fired.  Thus 

Ht 

(14) 


H0 

Under  such  a  definition  the  boiler  data  set  forth  in 
the  heat  balance  would  indicate  a  boiler  efficiency, 
thus 

14639 

Be  =  -         -  —  75.27% 
19450 

The  data  from  which  the  heat  balance  and  boiler 
efficiency  illustration  was  computed  in  this  chapter  is 
summarized  as  follows  : 

Summary  of   Data    Used 
Calorific  value  of  dry  fuel  oil  per  pound  ............  19,450    B.    t.    u. 

Equivalent  evaporation  of  water  per  hour  ............  28,225  Ib. 

Consumption  of  dry  fuel  oil  per  hour  ................   1  872   Ib. 

Steam  used  in  atomlzation  per  Ib.  of  dry  fuel  oil  .....  520  Ib. 

Temp,  of  saturated  steam  used  in  atomization  ......      381.9°  F. 

Temp,   of  feed  water  ................................       169.1°  F. 

Per  cent  of  moisture  in  fuel  oil  ......................          1.0% 

Temp,   of  entering  fuel  oil  ...........................         96°  F. 

Temp,   of  flue  gases  ..................................       400°  F. 

Hydrogen  content  of  fuel   ...........................         11.0% 

Carbon  content  of  fuel  .................  .  ............  .        86.  % 

Temp,    of    entering   air  ...............................        84°  F. 

Weight  of  dry  chimney  gases  per  Ib.  of  dry  fuel  .....        19.83  Ib. 

Weight  of  entering  air  per  Ib.  of  dry  fuel  oil  ........        21.82  Ib. 

Carbon  dioxide  in  flue  gas  ...........................          9.79% 

Carbon  monoxide   in  flue  gas  ........................          1.00% 

Moisture  of  entering  air  from  boiler  room  ............  .75% 


CHAPTER   XXXII 

SUMMARY  OF  SUGGESTIONS  FOR  FUEL 
OIL  TESTS  AND  THEIR  TABULATION 

The  rules  for  conducting  boiler  performances,  as 
advised  by  the  Power  Test  Committee  of  the  Ameri- 
can Society  of  Mechanical  Engineers,  covers  in  won- 
derful detail  the  setting  forth  of  apparatus  and  tabula- 
tion of  data  for  such  performances,  when  coal  is  em- 
ployed as  a  fuel.  Only  brief  mention  is,  however,  made 
for  alterations  necessary  when  crude  petroleum  is  used 
as  a  fuel.  Since  a  greater  number  of  engineers  would 
probably  be  inconvenienced  than  those  actually  bene- 
fited by  attempting  to  make  a  set  of  rules  broad  enough 
to  cover  both  performances  by  coal  and  by  oil  as  fuels, 
an  appendix  should  be  drawn  up  to  satisfy  standard- 
ized conditions  of  test  for  oil  fired  boilers.  This  lack 
of  standardized  performance  has  caused  considerable 
confusion  in  those  communities  where  oil  is  used  as  a 
fuel. 

The  most  glaring  source  of  confusion  is  that  relat- 
ing to  boiler  efficiency.  Sonie  engineers  maintain  that 
boiler  efficiency  is  the  ratio  of  heat  actually  transferred 
from  the  fuel  through  the  metallic  parts  of  the  boiler 
to  the  total  quantity  of  heat  given  out  by  the  fuel. 
When  coal  is  used  as  a  fuel  this  definition  is  perfectly 
proper,  but  when  oil  is  the  fuel  employed  confusion  is 
at  once  introduced,  due  to  the  fact  that  as  a  rule  a  cer- 
tain amount  of  the  steam  generated  must  be  utilized 
to  atomize  the  oil  in  the  furnace.  In  the  last  chapter  it 
was  shown  that  the  efficiency  of  an  oil  fired  boiler 
computed  on  one  assumption  in  a  specific  instance  is 
75.27  per  cent,  and  on  another  assumption  it  becomes 
but  72.37  per  cent. 

Let  us  then  discuss  some  of  the  points  wherein 
additional  instructions  are  desirable  to  properly  con- 
duct boiler  tests  where  oil  is  used  as  the  fuel  for  heat 
production. 

265 


266  FUEL  OIL  AND  STEAM  ENGINEERING 

Efficiency  for  Oil  Fired  Boilers  Defined. — Per- 
haps the  most  important  point  is  to  come  to  some 
definite  decision  relative  to  an  exact  manner  of  arriv- 
ing at  the  efficiency  of  the  boiler  as  above  alluded  to. 
In. this  work  we  shall  consider  that  the  true  efficiency 
of  the  boiler  and  furnace  is  to  be  found  by  taking  the 
ratio  of  the  heat  represented  in  the  steam  after  deduct- 
ing the  heat  used  for  atomization  purposes  to  the  total 
quantity  of  heat  given  out  by  the  fuel,  as  set  forth 
in  the  last  chapter.  On  the  other  hand  to  compute  the 
efficiency  of  the  boiler  shell  as  a  steam  producing 
agent,  we  shall  take  the  ratio  of  the  heat  of  all  steam 
generated  in  the  boiler  for  a  given  consumption  of 
fuel  to  the  total  heat  given  out  by  the  fuel.  The  effi- 
ciency of  a  boiler  and  furnace  is  as  a  rule  reduced  from 
2  to  5  per  cent  over  the  boiler  efficiency  as  a  steam 
producing  agent,  as  shown  in  the  previous  paragraph. 

Upon  invitation  of  the  Power  Test  Committee  of 
the  American  Society  of  Mechanical  Engineers,  the 
authors  of  this  work  have  presented  proposals  to  the 
Society  to  meet  this  growing  need  in  standardization. 

In  these  tables  the  item  numbers  have  been  re- 
tained as  far  as  possible  to  correspond  with  the  item 
numbers  in  the  code  of  1915.  The  principal  changes 
consist  in  the  following :  The  omission  of  reference  to 
grates  and  grate  surface  and  substituting  therefor  the 
number  of  oil  burners  and  dimensions  of  furnace ;  the 
omission  of  reference  to  ash,  combustible,  firing  data, 
etc.,  but  introducing  instead  items  connected  with  the 
steam  used  for  atomizing  the  oil  at  the  burner.  The 
term  "net  efficiency"  is  also  introduced,  by  which  is 
meant  the  efficiency  of  the  boiler  as  discussed  on 
page  263. 

In  addition  to  the  tabulations  submitted,  the 
writers  have  suggested  that  the  appendix  in  the  Code 
Rules  be  amplified  so  as  to  include  a  description  of 
methods  for  obtaining  gravity  of  oils,  flash  point,  the 
water  content  and  the  viscosity.  These  determina- 
tions could  be  fully  described  and  included  in  Appen- 
dix Xo.  14,  beginning  with  paragraph  287  under  the 
heading  "Analysis  of  Liquid  Fuels." 


TABULATION  OF  TEST  DATA  267 

TABULATION     OF     FUEL     OIL     TEST     DATA 

Table  1.    Data  and   Results  of   Evaporative  Test. 

Adapted   from   Code   of   1915 

(1)*         Test  of boiler  located  at 

to  determine conducted  by 

(2)  Number  and  kind  of  boilers 

(3)  Kind   of   furnace 

(a)  Type  of  burner   

(b)  Make  of  burner 

(c)  Number    of    burners 

(4)  Furnace  dimensions   width length height.  . .  . 

(a)  Approximate  area  of  air  opening's  in  furnace  floor.  ..  .sq.  in. 

(b)  Approximate  area  of  air  openings  around  burners.  ..  .sq.  in. 

(c)  Total  area   of  air  openings    sq.  in. 

(d)  Total  area  of  air  openings    per  rated  horsepower sq.  ft. 

(e)  Volume  of  furnace cu.  ft. 

(f)  Distance  from  furnace  floor  to  nearest  heating  surface.  . .  .ft. 

(5)  "Water  heating  surface sq.  ft. 

(6)  Superheating   surface    sq.  ft. 

(7)  Total  heating  surface sq.  ft. 

Date,  Duration,   Etc. 

(8)  Date    

(9)  Duration    hr. 

(10)  Kind  of  fuel  oil 

(a)  Gravity  of  fuel  oil  at  60  deg.   (specific  gravity) 

(b)  Gravity  of  fuel  oil  at  60  deg.   (Baume  scale) 

(c)  Flash   point  of   oil    deg. 

(d)  Viscosity  of  oil  at deg deg.   Engler. 

(e)  Method  of  atomizing  oil 

Average  Pressures,  Temperatures,  Etc. 

(11)  Steam  pressure  by  gage  in  boiler Ib.  per  sq.  in. 

(a)  Steam  pressure  at  superheater  outlet Ib.  per  sq.  in. 

(b)  Steam  pressure  at  oil  burners Ib.  per  sq.  in. 

(c)  Oil  pressure  at  burner Ib.  per  sq.  in. 

(d)  Barometric  pressure    ins.  of  mercury. 

(12)  Temperature  of  steam  at  superheater  outlet deg. 

(a)  Normal   temperature  of  saturated   steam deg. 

(b)  Temperature  of  steam  at  oil  burner deg. 

(c)  Temperature  of  oil  at  burner deg. 

(13)  Temperature  of  feed  water  entering  boiler deg. 

(a)  Temperature  of  feed  water  entering  economizer deg. 

(b)  Increase  of  temperature  of  water  due  to  economizer.  . .  .deg. 

(14)  Temperature  of  gases  leaving   boilers deg. 

(a)  Temperature  of  gases  leaving  economizer deg. 

(b)  Decrease  of  temperature  of  gases  due  to  economizer. .  .deg. 

(c)  Temperature    of    furnace deg. 

(15)  Draft  between  damper  and  boiler ins.  of  water 

(a)  Draft  in  main  flue  near  boilers ins. 

(b)  Draft  in  main  flue  between  economizer  and  chimney.  ..  .ins. 

(c)  Draft   in   furnaces ins. 

(d)  Draft  in  ash  pits ins. 

(16)  State   of   weather 

(a)  Temperature  of  external  air deg. 

(b)  Temperature  of  air  entering-  ash  pit deg. 

(c)  Relative  humidity  of  air  entering  ash  pit per  cent. 

Quality  of  Steam 

(17)  Percentage  of  moisture  in  steam  or  number  of  degrees 

of  superheating per  cent,  or  deg. 

(18)  Factor  of  correction  for  quality  of  steam 

Total  Quantities 

(19)  Weight  of  fuel  oil  as  flredt Ib. 

(20)  Percentage  of  water  in  fuel  oil  as  fired per  cent. 

(21)  Total  weight  of  water  free  fuel   oil  consumed Ib. 

(25)  Total  weight  of  water   fed    to   boiler Ib. 

(26)  Total  water  evaporated  corrected  for  quality  of  steam.  .  .Ib. 

(a)  Total  weight  of  steam  fed  to  burner Ib. 

(b)  Steam    fed    to    burner    in    per  cent,    of    total    water 

evaporated per  cent. 

*These   numbers   correspond   in   so  far  as   possible   with   numbers 
given  in  the  A.  S.  M.  E.  Code  of  1915. 

fThe  term  "as  fired"  means  actual  conditions,  including  moisture. 


268  FUEL  OIL  AND  STEAM  ENGINEERING 

(27)  Factor    of    evaporation,    based    on    temperature    of 

water  entering  boilers 

(28)  Total  equivalent  evaporation  from  and  at  212  deg.f lb. 

Hourly  Quantities  and  Rates 

(29)  Oil  free  from  water  consumed  per  hour lb. 

(30)  Oil  free  from  water  per  hour  per  burner lb. 

(a)  Oil  free  from  water  per  cu.   ft.   of  furnace  volume 

per   hour    lb. 

(31)  Water  evaporated  per  hour,  corrected  for  quality  of 

steam lb. 

(a)  Steam  fed  to  burners  per  hour lb. 

(b)  Equivalent    evaporation    from    and    at  212   deg.   of 

steam  fed  to  burner  per  hour lb. 

(32)  Equivalent  evaporation  per  hour  from  and  at  212  deg.f lb. 

(33)  Equivalent   evaporation   per   hour  from   and   at  212 

deg.  per  sq.  ft.  of  water  heating  surface lb. 

Capacity 

(34)  Equivalent   evaporation   per   hour   from   and  at   212 

deg.   (same  as  line  32 ) lb. 

(a)  Boiler  horsepower  developed   (line  32   -f-  34%) Bl.   H.  P. 

(35)  Rated  capacity  per  hour,  from  and  at  212  deg lb. 

(a)  Rated  boiler  horsepower   Bl.   H.   P. 

(36)  Percentage  of  rated  capacity  developed per  cent. 

Economy 

(37)  Water  fed  per  lb.  of  fuel  oil  as  fired  (item  25-^-iteml9) . .  .lb. 

(38)  Water  evaporated  per  lb.  of  water  free  fuel  oil  (item 

26  -=-  item  21) lb. 

(39)  Equivalent  evaporation  from  and  at  212  deg.  per  lb. 

of  fuel  oil  as  fired  (item  28  -=-  item  19) lb. 

(40)  Equivalent  evaporation  from  and  at  212  deg.  per  lb. 

of  water  free  fuel  oil  (item  28  -f-  item  21) lb. 

(a)  Equivalent     evaporation    from    and   at   212   deg.    of 

steam  fed  to  burner  per  lb.  of  fuel  oil  free  from 

water  (item  26a  X  item  27  -=-  item  21) lb. 

(b)  Net  equivalent  evaporation  from  and  at  212  deg.  per 

lb.  of  oil  free  from  water  (item  40  — <  item  40a) lb. 

Calorific  Value 

(42)         Calorific  value   of   1   lb.    of  fuel   oil   as   received   by 

calorimeter B.  t.  u. 

(a)  Calorific  value  of  1  lb.  of  water  free  fuel  oil B.  t.  u. 

Efficiency 
(44)         Efficiency  of  boiler  and  furnace. 

Item  40  X  970.4 

100  X  Per  cent. 

Item   42a 

(a)  Net  .efficiency  of  boiler  and  furnace. 

Item  40b  X  970.4 

100  X  Per  cent. 

Item   42a 

Cost  of  Evaporation 

(46)  Cost  of  fuel  oil  per  bbl.  of  42  gals,  delivered  in  boiler 

room dollars. 

(47)  Cost  of  fuel  oil  required  for  evaporating  1000  lb.  of 

water  under  observed  conditions dollars. 

(48)  Cost  of  fuel  oil  required  for  evaporating  1000  lb.  of 

water  from  and  at  212  deg dollars. 


fThe  symbol  U.  E.,  meaning  Units  of  Evaporation,  may  be  sub- 
stituted for  the  expression  "Equivalent  Evaporation  from  and  at 
212  deg." 


TABULATION  OF  TEST  DATA  269 

Smoke  Data 

(49)         Percentage  of  smoke  as  observed per  cent. 

(a)  Weight  of  soot  per  hour  obtained  from  smoke  meter 

(51)         Analysis  of  Dry  Gases  by  Volume. 

(a)  Carbon  dioxide  (CO2)   per  cent. 

(b)  Oxygen    (O)    per  cent. 

(c)  Carbon  monoxide   (CO)    per  cent. 

(d)  Hydrogen  and  hydrocarbons  per  cent. 

(e)  Nitrogen,  by  difference  (N)   per  cent. 

(53)         Ultimate  analysis  of  fuel  oil. 

(a)  Carbon    (C)    per  cent. 

(b)  Hydrogen   (H)    per  cent. 

(c)  Oxygen   (O)    per  cent. 

(d)  Nitrogen   (N)    per  cent. 

(e)  Sulphur  (S)    per  cent. 

(f )  Ash per  cent. 

100  per  cent. 

(g)  Water  in  sample  of  fuel  oil  as  received per  cent. 

(55)         Heat  balance,  based  on  fuel  oil  free  from  water: 

Fuel  Oil  Free  FromWater 
B.  t.  u.  Per  Cent. 

(a)  a.  Total  heat  absorbed  by  boiler. . 

b.  Heat   absorbed    for   atomization 

c.  Net  heat  absorbed  for  power. . . 

(b)  Loss  due  to  water  in  fuel  oil 

(c)  Loss  due  to  water  from  burning  H 

(d)  Loss  due  to  heat   carried   away   by 

dry  gases   For  numerical 

(e)  Loss  due  to  carbon  monoxide.....  example   com- 

(f)  a.  Loss     due     to     evaporation     of  pletely  solved, 

steam  for  atomization see  page  263. 

b.  Loss  due  to  superheat  of  steam 

used   for  atomization 

c.  Total  loss  due  to  atomization. . . 

(g)  Loss  due   to   moisture   in   entering 

air    

(h)  Stray  losses    

(i)    Total  calorific  value  of  1  Ib.  of  fuel 

oil  free  from  water  (item  42a)  100 

Table  2 
Principal    Data    and    Results    of    Boiler    Test 

(1)  Oil  Burners.— No Type Make 

(2)  Total    heating    surface sq.  ft. 

(3)  Date    

(4)  Duration hr. 

(5)  Kind  and  gravity  of  fuel  oil 

(6)  Steam  pressure  by  gage Ib.  per  sq.  in. 

(a)   Oil  pressure  at  burner Ib.  per  sq.  in. 

(7)  Temperature  of  feed  water  entering  boiler deg. 

(a)   Temperature  of  oil  at  burner deg. 

(8)  Percentage   of  moisture   in    steam   or   number  of  de- 

grees of  superheating per  cent,  or  deg. 

(9)  Percentage  of  water  in  oil per  cent. 

(10)  Oil  free  from  water  per  hour Ib. 

(11)  Oil  free  from  water  per  hour  per  burner Ib. 

(12)  Equivalent  evaporation  per  hour  from  and  at  212  deg Ib. 

(13)  Equivalent  evaporation  per  hour  from  and  at  212  deg. 

per  sq.  ft.  of  heating  surface Ib. 

(14)  Rated  capacity  per  hour,  from  and  at  212  deg Ib. 

(15)  Percentage  of  rated  capacity  developed per  cent. 

(16)  Equivalent  evaporation  from  and  at  212  deg.   per  Ib. 

oil  free  from  water Ib. 

(a)  Per  cent,  of  total  steam  used  by  burner percent. 

(17)  Net  equivalent  evaporation  from  and  at  212  deg.  per 

Ib.  of  oil  free  from  water  (deducting  steam  used 

by  burner)    Ib. 

(18)  Calorific  value  of  1  Ib.  of  oil  as  received,  by  calorimeter.  .B.t.u. 

(19)  Calorific  value  of  1  Ib.  of  oil  free  from  water B.t.u. 

(20)  Efficiency  of  boiler  and  furnace per  cent. 

(21)  Net  efficiency  (deducting  steam  used  by  burners). ..  .per  cent. 


CHAPTER   XXXIII 

THE   USE   OF   EVAPORATIVE   TESTS   IN   IN- 
CREASING EFFICIENCY  OF  OIL 
FIRED    BOILERS 

To  the  operating  engineer  it  may  seem  that  the 
somewhat  elaborate  rules  for  conducting  evaporative 
tests  of  steam  boilers  are  of  little  interest.  It 
is  his  province  to  run  the  boilers  as  economically  as 
he  can,  to  keep  them  clean  and  in  proper  repair,  and 
above  all  to  keep  the  plant  in  continuous  operation. 
There  is  one  very  important  function  of  boiler  tests, 
however,  which  makes  them  invaluable  to  the  broad- 
gage  operating  engineer  who  is  desirous  of  securing 
the  best  possible  results  from  his  plant.  This  is  the 
use  of  the  evaporative  test  as  a  guide  in  determining 
what  is  the  best  furnace  arrangement,  the  best  style 
of  oil  burner,  and  the  best  draft  conditions  for  the  par- 
ticular boilers  he  is  operating.  Thus  by  making  a  care- 
ful test  under  certain  conditions  and  then  making  an- 
other test,  or  sometimes  a  series  of  tests,  under  differ- 
ent conditions,  it  is  possible  to  determine  from  the  rel- 
ative efficiencies  obtained  just  how  the  boiler  should 
be  operated.  It  will  not  be  out  of  place,  therefore,  to 
discuss  briefly  the  various  changes  that  may  be  made 
in  the  boiler  operation,  which  when  intelligently  car- 
ried out  will  lead  to  higher  efficiencies. 

Furnace  Arrangement. — Perhaps  the  most  impor- 
tant part  of  an  oil  fired  boiler  is  its  furnace  arrange- 
ment. In  a  previous  chapter  a  number  of  different  fur- 
naces were  described,  but  it  was  not  stated  which  was 
the  most  efficient.  This  must  be  determined  by  test- 
ing the  boiler  under  actual  operating  conditions,  first 
with  one  furnace  arrangement,  then  with  another,  be- 
ing guided  in  making  changes  by  the  results  obtained 
in  the  different  tests.  It  is  impossible  to  design  a  fur- 

270 


INCREASING  EFFICIENCY  271 

nace  that  will  be  right  for  all  conditions,  as  with  dif- 
ferent grades  of  fuel  oil  or  different  makes  of  boiler  or 
different  draft  conditions,  different  furnace  arrange- 
ments are  required.  Fortunately  it  is  possible  to  make 
minor  changes  in  the  furnace  very  easily,  as  these  in- 
volve usually  only  an  alteration  of  the  location  of  fire 
brick  on  the  furnace  floor.  It  is  thus  possible  to  in- 
crease or  decrease  the  size  of  air  openings,  or  to  change 
them  in  such  a  way  as  to  allow  more  air  to  enter  at 
one  part  of  the  furnace,  such  as  directly  under  the 
flame,  and  less  at  another  part  where  it  is  not  needed. 
It  is  also  possible,  without  much  difficulty,  to  alter  a 
furnace  that  has  been  designed  for  a  front  shot  burner 
and  make  it  suitable  for  a  back  shot  burner,  and  thus 
it  may  be  found  by  actual  tests  which  of  these  two 
types  of  furnace  is  best  suited  to  the  particular  boiler. 

In  testing  the  different  arrangements  it  is  very 
important  to  test  the  boiler  for  capacity  as  well  as 
economy,  as  it  may  sometimes  happen  that  the  fur- 
nace that  is  most  efficient  at  ordinary  loads  is  not 
capable  of  forcing  the  boiler  enough  to  carry  the  heavy 
loads  sometimes  required.  In  such  a  case  it  may  be 
necessary  to  adopt  a  less  efficient  furnace,  as  it  is 
usually  of  supreme  importance  for  the  boiler  to  be 
capable  of  carrying  an  overload  when  required. 

Oil  Burners. — Boiler  tests  are  of  great  value  in 
determining  what  make  and  style  of  oil  burner  is  the 
best  to  use  under  the  given  conditions.  In  testing  oil 
burners  it  is  of  extreme  importance  to  measure  the 
steam  used  by  the  burner  and  determine  the  net  effi- 
ciency of  the  boiler;  for  one  kind  of  burner  may  pro- 
duce better  furnace  efficiency  than  another,  and  yet 
use  so  much  steam  for  atomizing  as  to  make  it  an  un- 
economical burner  to  use.  After  deciding  on  the  type 
of  burner  to  use,  tests  should  be  made  with  varying 
quantities  of  atomizing  steam  with  the  same  burner, 
the  object  being  not  to  find  out  the  least  quantity  of 
steam  that  may  be  used  for  atomizing  but  to  deter- 
mine the  quantity  of  steam  that  secures  the  best  net 
efficiencv  of  the  boiler. 


UJ     «- 


O  e8  ft 

o  gc 


Q  g'aJ'S.c: 

Q.  "03*  ^  'S  °  2 

°-  3    .M^O- 

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_J  <p  03        M+J 


o        5 

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Illltl 

18  O  -3  as  ft  a, 

o>  O  S  i>  3  -^ 


INCREASING  EFFICIENCY  273 

The  temperature  and  pressure  of  the  oil  are  inti- 
mately connected  with  the  quantity  of  atomizing 
steam  required.  In  the  case  of  mechanical  atomiza- 
tion,  such  as  is  used  in  marine  work,  high  pressure  and 
high  temperatures  are  used  and  no  steam  is  required. 
In  general  it  may  be  said  that  the  hotter  the  oil  and 
the  higher  its  pressure,  the  less  atomizing  steam  is 
needed.  Different  oils  require  different  temperatures, 
and  the  temperature  should  always  be  kept  well  below 
the  flash  point  of  the  oil.  By  testing  the  boiler  with  the 
oil  first  at  one  temperature  and  then  at  another,  and 
varying  the  quantity  of  steam  to  suit,  much  informa- 
tion can  be  obtained  as  to  the  most  economical  method 
of  operation. 

Apart  from  the  quantity  of  steam  used,  other 
changes  that  may  be  made  in  the  burner  consist  in 
varying  the  size  of  the  steam  and  oil  slots,  altering  the 
height  of  the  burner  in  reference  to  the  furnace  floor, 
and  changing  the  angle  of  the  flame  in  reference  to 
the  grates. 

Draft. — The  quantity  of  air  entering  the  furnace 
depends  on  the  intensity  of  the  draft,  and  the  area  of 
openings  for  the  admission  of  air  to  the  furnace.  The 
quantity  of  air  may  be  reduced  by  partially  closing  the 
boiler  damper  or  the  ash  pit  doors,  or  it  may  be  in- 
creased by  enlarging  the  openings  in  the  furnace  floor. 
Thus  it  is  possible  to  operate  with  large  openings  and 
light  draft,  or  with  small  openings  and  strong  draft. 
A  careful  test  of  the  boiler  will  determine  at  once 
which  of  these  conditions  gives  the  best  results.  If 
the  load  on  the  plant  is  variable  it  is  necessary  to  have 
the  air  openings  large  enough  to  admit  sufficient  air 
for  the  maximum  load  at  full  draft.  Then  for  lighter 
loads  the  damper  or  ash  pit  doors  must  be  operated. 
When  making  tests  the  readings  of  the  draft  gage  at 
various  points  in  the  setting  should  be  carefully  ob- 
served, and  loss  of  draft  due  to  the  gases  passing 
through  the  setting  noted.  Thus,  if  the  draft  in  the 
furnace  is  .2  in.  and  the  draft  in  front  of  the  damper  is 
.3  in.,  there  is  a  loss  of  1  in.  between  the  damper  and 
the  furnace.  This  loss  of  draft  varies  with  the  volume  of 


FUEL  OIL  AND  STEAM  ENGINEERING 


INCREASING  EFFICIENCY  275 

gases  just  as  the  drop  in  pressure  due  to  steam  flowing 
through  an  orifice  varies  with  the  quantity  of  steam 
flowing.  If  the  quantity  of  excess  air  increases,  there- 
fore, the  loss  of  draft  also  increases.  By  connecting  a 
draft  gage  so  as  to  measure  the  difference  in  the  draft 
at  the  two  points,  it  will  serve  as  an  approximate  indi- 
cator of  the  amount  of  excess  air. 

Flue  Gas  Analysis  for  Maximum  Efficiency. — The 
analysis  of  the  flue  gases  serves  as  an  accurate  means 
of  determining  how  to  set  the  dampers,  and  is  the  most 
valuable  guide  in  securing  the  best  efficiency,  both 
during  an  evaporative  test  and  in  regular  operation. 
In  general,  it  may  be  said  that  the  best  efficiency  is  ob- 
tained when  the  greatest  percentage  of  carbon  di- 
oxide (CO2)  occurs,  without  the  presence  of  carbon 
monoxide  (CO).  If  CO  begins  to  appear  in  the  gas 
analysis  it  is  useless  to  increase  the  CO2  further,  as  any 
gain  due  to  reducing  the  excess  air  is  more  than  offset 
by  the  loss  due  to  incomplete  combustion.  The  pres- 
ence of  CO  is  always  more  harmful  than  is  indicated 
by  the  calculated  loss  for  unconsumed  carbon,  for  if 
carbon  is  only  partially  consumed  it  is  certain  that 
some  of  the  hydrogen  is  also  passing  off  unconsumed 
in  the  form  of  hydrocarbons,  thus  causing  a  far  greater 
loss.  This  loss  due  to  unconsumed  hydrogen  does  not 
appear 'in  the  ordinary  gas  analysis,  and  it  is  in  con- 
nection with  this  item  that  the  heat  balance  is  of 
special  value.  Item  (h)  of  the  heat  balance,  which  is 
found  by  subtracting  the  heat  accounted  for  from  the 
heat  supplied,  includes  the  loss  due  to  unconsumed  hy- 
drogen, and  if  accurate  tests  are  made  it  will  be  found 
that  this  item  is  always  greater  the  more  CO  is  found 
in  the  gases. 

If  the  furnace  is  properly  designed  it  should  be 
possible  to  secure  l3l/2%  to  14%  CO2,  with  not  over 
3%  oxygen,  and  without  a  trace  of  CO,  using  not  over 
15%  or  20%  excess  air.  These  results  must  be  se- 
cured to  give  the  best  economical  results,  and  if  they 
cannot  be  secured  by  changing  the  draft  or  the  burn- 
ers, it  will  then  follow  that  there  is  something  wrong 
with  the  furnace  arrangement. 


276 


FUEL  OIL  AND  STEAM  ENGINEERING 


It  will  be  found  that  there  is  a  very  intimate  rela- 
tion between  the  furnace,  the  burner,  and  the  draft. 
Thus  the  intensity  of  draft  and  amount  of  atomizing 
steam  that  give  best  results  with  one  furnace,  may 
give  poor  results  with  another;  yet  by  readjusting  the 
dampers  and  burner  valves  to  suit  the  new  conditions, 
better  results  than  ever  may  be  obtained.  With  too 
much  steam  the  flame  may  be  carried  too  far  beyond 
the  air  openings,  causing  a  poor  mixture  of  air  and 


A    TYPICAL    AUTOMATIC    SYSTEM    OF    CONTROL 

Diagramatic  View,  showing  Manner  of  Control  for  the  Oil,  the 
Ashpit  and  the  Damper: 

A.  Master  Controller  E.  Single  Bearings  I.  Damper  Weights 

B.  Double  Oil  Strainer  F.  Damper  Arms     J.  Interlocking  Damper 

C.  Oil  Gage  G.  devices  K.  Special  Brackets 

D.  Regulator  H.  Damper  Hubs 

gases.     This  would  result  in  a  poor  gas  analysis,  al- 
though the  total  quantity  of  air  may  be  correct. 

There  are  so  many  variations  that  can  be  made, 
that  it  is  usually  impractical  to  make  a  complete 
evaporative  test  for  each  set  of  conditions.  It  is  pos- 
sible, however,  to  obtain  comparative  data  in  a  single 
test,  by  varying  the  conditions  at  the  end  of  each  hour, 
or  each  two  hours.  By  carefully  observing  the  quan- 


INCREASING  EFFICIENCY 


277 


tity  of  oil  and  water  used  each  hour,  a  fairly  accurate 
comparison  of  efficiencies  under  different  conditions 
may  be  obtained.  This,  combined  with  the  flue  gas 
analysis,  makes  a  valuable  guide  for  efficient  opera- 
tion. 

BOILER   OPERATION    REPORT 
PACIFIC  GAS  AND  ELECTRIC  COMPANY        OPERATION  AND  MAINTENANCE  DEPT 

OBSERVATIONS  ON  BOILER  No. IN  STATION 

DATE  OBSERVATIONS  BY 

RATED  H.P TUBES  HIGH TUBES  WIDE No.  DRUMS 


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TYPICAL  FORM   FOR   BOILER  OPERATION    REPORT 

Here  is  how  the  Pacific  Gas  &  Electric  Company,  a  corporation 
operating  the  largest  system  of  oil-fired  steam  power  plants  in  the 
world,  keeps  its  records  on  evaporative  tests  for  bettering  power 
plant  economy. 

Regulation — When  an  oil  fired  boiler  is  in  opera- 
tion there  are  three  variables  under  control  of  the  fire- 
man, viz. : 


278  FUEL  OIL  AND  STEAM  ENGINEERING 

The  quantity  of  oil  burned. 

The  quantity  of  atomizing  steam  used,  and 

The  quantity  of  air  supplied. 

The  quantity  of  oil  burned  is  determined  by  the 
amount  of  steam  required  in  the  plant,  and  must  be 
varied  accordingly.  When  there  are  several  boilers  in 
battery  the  amount  burned  under  each  boiler  may  be 
varied  by  operating  the  oil  valves  at  the  burners,  or 
the  total  amount  in  the  plant  may  be  changed  by  alter- 
ing the  oil  pressure  at  the  oil  pump.  Whenever  the 
quantity  of  oil  burned  is  varied,  there  should  be  a  cor- 
responding variation  in  the  quantity  of  atomizing 
steam  and  the  quantity  of  air. 

There  are  now  on  the  market  devices  which  regu- 
late all  three  variables  automatically  according  to  the 
load  on  the  plant.  Illustrations  of  automatic  firing 
systems  are  shown  on  pages  12,  274,  and  276.  The  es- 
sential requisites  for  a  device  of  this  kind  are  that  it 
shall  be  reliable  in  operation,  and  that  when  it  has  once 
been  set  to  give  proper  CO2  readings  at  certain  loads, 
it  will  always  come  back  to  the  same  position  for  the 
same  load.  While  it  is  possible  under  test  conditions 
to  secure  just  as  high  efficiency  writh  hand  regulation 
as  with  the  automatic,  it  will  usually  be  found  that 
the  automatic  regulator  produces  better  every-day 
economy  under  operating  conditions. 

Records. — Complete  evaporative  tests  cannot  be 
made  every  day  in  an  ordinary  plant,  but  it  is  possible 
to  take  sufficient  observations  to  secure  a  daily  rec- 
ord of  the  important  items  entering  into  the  operation 
of  a  boiler.  A  form  that  is  convenient  for  such  a  rec- 
ord is  illustrated  in  the  accompanying  cut.  By  care- 
fully studying  these  records,  together  with  the  results 
of  evaporative  tests,  it  is  possible  to  maintain  the 
operation  of  a  boiler  plant  at  a  very  efficient  point. 

By  operation  at  the  most  efficient  point  we  save 
and  it  is  well  to  remember  in  these  days  of  national 
crisis,  that  "to  save  is  to  serve." 


APPENDIX  I 

ILLUSTRATIVE   PROBLEMS 

Problem  No.  1 — The  mean  effective  pressure  of  a  single- 
acting  oil  engine  cylinder  under  test  is  found  from  an  indi- 
cator card  to  be  43.9  Ib.  per  sq.  in.;  the  cylinder  has  47.5 
working  strokes  per  minute;  the  diameter  of  the  cylinder  is 
30  in.;  and  the  length  of  stroke  is  30  in. 

What  is  its  horsepower? 

Solution. 

By  reference  to  formula  for  horsepower  computation,  we 
find  for 

30 

P  —  43.9,  L  —  — ,  A  —  .7854  (30)2,  and  N  =  47.5  that 
12 

PLAN          43.9  X  2.5  X  706.9  X  47.5 
H.  P.  —  -  -  =  111.7 

33000  33000 

Problem  No.  2 — In  a  turbine  test  the  atmr spheric 
barometer  reduced  to  the  32°  F.  standard  of  measurement, 
read  29.93  in. 

If  the  condenser  vacuum  reduced  to  the  same  standard 
read  28.23  in.  of  vacuum,  what  was  the  absolute  pressure  in 
the  condenser? 

Solution. 

Barometer  for  day   29.93  in. 

Vacuum  maintained 28.23  in. 


Pressure  in  condenser  in  inches  of  mercury.  .       1.70  in. 
14.696  Ibs.  per  sq.  in.  =  29.92  in.  of  mercury. 

14.696  29.92 


X  1.70 

14.696 

X  =  -        -  X  1.70  =  .835  Ibs.  per  sq.  in.  ab- 
29.92  solute     pressure     in 

condenser. 

279 


280  FUEL  OIL  AND  STEAM  ENGINEERING 

Problem  No.  3 — A  10,000  kw.  turbine  under  test  operated 
with  a  gage  reading  of  171.5  Ib.  per  sq.  in.  The  gage,  how- 
ever, read  one  pound  too  low.  The  computed  absolute  pressure 
was  found  to  be  187.2  Ib.  per  sq.  in. 

What  was  the  barometer  reading  for  the  day? 

Solution. 

Absolute   pressure    =  187.2  Ib.  per  sq.  in. 

Corrected  gage  pressure 

(171.5  +  1)  .=  172.5  Ib.  per  sq.  in. 


Atmospheric  pressure  =     14.7  Ib.  per  sq.  in. 

14.696  29.92 


14.7  X 

29.96 

X  =:  -        -  X  14.7  =  29.93  in.  of  mercury  ba- 
14.696  rometer    reading 

for  the  day. 

Problem  No.  4 — A  corrected  atmospheric  barometer  read- 
ing is  found  to  be  29.942  in.  of  mercury  on  the  32°  F.  standard. 
How  many  Ibs.  per  sq.  in.  does  this  represent? 

Solution. 

To  convert  to  Ib.  per  sq.  in.  by  formula  in  the  chapter 
on  pressures: 

I™  29.921 


P      14.696 
or  29.942  =  2.046  P 

.'.  P  =  14.670  Ib.  per  sq.  in. 

Problem  No.  5 — A  corrected  barometer  reading  is  29.937 
in.  of  mercury  on  the  30-inch  vacuum  standard. 
What  is  the  pressure  in  Ib.  per  sq.  in.? 

Solution. 

To    convert    to    Ibs.    per    sq.    in.    from    formula    in   the 
chapter  on  pressures : 

In,  30 


P  14.7 

or     29.937  =     2.041  P 

.'.  P  =  14.668  Ib.  per  sq.  in. 


ILLUSTRATIVE  PROBLEMS  281 

Problem  No.  6— (a)  At  what  temperature  do  the  Fahren- 
heit and  Centigrade  scales  read  the  same?  Fahrenheit  and 
Reamur?  Centigrade  and  Reamur? 

(b)  Assuming  the  absolute  zero  of  the  Fahrenheit  scale 
to  be  459.6°  F.  compute  the  absolute  zero  on  the  Centigrade 
and  Reamur  scales. 

Solution. 

(a)   Fahrenheit  and  Centigrade. 
Relation  is  given  by  formula: 

F  —  32  =  9/5C 
When    the    scales    have   identical    numerical    readings,    then 

F  r=  C  —  X 
Substituting  in  formula 

X  —  32  =  9/5X 

4X  =  —160  or  X  =  —40° 

.'.  —  40°F  =  —  40°C. 

Fahrenheit  and    Reamur. 
Relation  is  given  by  formula: 

F  —  32  =  9/4R 

Let  F  =  R  =  X,      then  X  —  32  =  9/4X 
5X  =  —128,         or  X  =  —25.6 

.'.  — 25.6°F.  =  — 25.6°R. 

Centigrade  and  Reamur. 
Relation  is  given  by  formula: 

C  =  5/4R 
Let  C  =  R  =  X,       then  X  =  5/4X 

4X  =  5X  or      X  =  0 

.'.     0°C  =  0°R 

(b)     Absolute  zero  =  — 459.6°  F. 

Let  us  substitute  this  value  of  F  in  the  general  relation- 
ship, and  we  have 

F  —  32  —  9/5C 
and  we  have 

—459.6  —  32  =  9/5C 

9C  =  — 2458  or  C  =  — 273.1°  absolute  zero  on 

Cent,  scale. 
Similarly  for  the  relationship 

F  —  32  =  9/4  R 
we  have 

—459.6  —  32  =  9/4R 

9R  =  —1966.4 

R  =  — 218.049  =  absolute  zero  on 
Reamur  scale. 


282  FUEL  OIL  AND  STEAM  ENGINEERING 

Problem  No.  7 — The  temperature  of  the  steam  entering 
a  turbine  during  a  test  was  found  to  be  521.2°  F.;  the  correc- 
tion for  stem  exposure  of  the  thermometer  was  5.6°  F.;  the 
corrected  steam  gage  reading  172.5  Ib.  gage;  and  the  at- 
mospheric barometer  read  14.7  Ib.  per  sq.  in. 

What  was  the  superheat  of  the  steam? 

Solution. 

Thermometer  reading  on  entering  steam    =  521.2° 
Correction  for  stem  exposure                           ==+      5.6° 
True    temp,  of  steam  entering  turbine          =  526.8°  F. 
Absolute  pressure  =  172.5  +  14.7                  =  187.2  Ib. 
From   steam   tables   the   temperature  cor- 
responding to  this  pressure  of  satu- 
rated dry  steam                                        =  376.4°  F. 
.'.  Degrees  of  superheat  =  526.8°  —  376.4°  =  150.4° 

Problem  No.  8 — The  temperature  of  the  superheated 
steam  entering  a  turbine  during  a  test  was  found  to  be  544.8° 
F.  The  pressure  of  the  steam  in  the  main  was  182  Ibs.  abs. 

What  was  the  superheat  of  the  steam? 

Solution. 

By  reference  to  Table  2  of  the  steam  tables  the  temper- 
ature of  saturated  steam  corresponding  to  182  Ibs.  pressure 
is  found  to  be  374.0°  F.  Subtract  this  value  from  the  temper- 
ature of  the  steam  entering  the  turbine  and  the  result  will 
be  the  degrees  of  superheat,  or 

544.8  —  374.0  =  170.8°  F.  superheat 

Problem  No.  9 — Regnault's  classic  formula  for  total  heat 
of  saturated  steam  is: 

H  =  1091.7   +   0.305    (t— 32) 

Compute  the  total  heat  of  saturated  steam  at  the  boiler 
pressure  corresponding  to  382.3°  F. 

Solution. 

Substituting,  we  have 

H  =  1091.7  +  0.305  (382.3—32) 
=  1091.7  +  106.84 
=  1198.54  B.  t.  u.  per  Ib. 
From  tables  H  =  1198.2 

1198.54  —  1198.2  .34 

.'.  Error  —     ; 

1198.2  1198. T 

=  .0284% 


ILLUSTRATIVE  PROBLEMS  283 

Problem    No.   10 — Compute   the  total   heat   of  saturated 
steam  at  382.3°  F.  by  the  formula: 

H  =  1150.3  +  0.3745   (t— 212)  —  0.000550   (t— 212)2 

Solution. 

Substituting  the  value  of  temperature,  we  have 
H  =:  1150.3  +  0.3745  (382.3—212)  —  0.000550  (382.3— 212)2 

=  1150.3  +  63.78  —  15.95 

=  1198.13  B.  t.  u.  per  Ib. 

From  tables  H  —  1198.2 

1198.2  —  1198.13              .07 
. ' .  Error  = =  


1198.2  1198.2 

=  .00585% 

Problem  No.  11 — The  specific  volume  of  saturated  steam 
is  represented  on  page  104  of  Marks  and  Davis  Steam  Tables 
by  the  formula : 

S  =  28.424—  0.01650  (t— 320)  —  0.0000132  (t— 320)2 
Find  the  specific  volume  of  steam  for  t  =  382.3. 

Solution. 

Substituting,  we  have 

8  =  28.424  —  0.01650  (382.3— 320)— 0.0000132  (382.3— 320)2 
=  28.424  — .862  — .036 
=  29.525 

N.  B. — This  formula  evidently  does  not  check  up  at  all  for 
this  temperature,  since  the  specific  volume  for  a  temperature 
of  382.3°  F.  is  2.279  from  the  steam  tables. 

Problem  No.  12 — The  mean  specific  heat  of  steam  is  repre- 
sented mathematically  on  page  92  of  Marks  &  Davis  Steam 
Tables  by  the  formula: 

Cm  =  0.9983  —  0.0000288  (t  — 32)  —  0.0002133  (t— 32)2 
What  is  the  mean  specific  heat  of  steam  for  t  =  382. 3°F.? 

Solution. 

Substituting,  we  have 

C,,,  =  0.9983  —  0.0000288  (382.3  —  32)  +0.0002133  (382.3  —  32)- 
=  0.9983  —  0.0000288  (350.3)  +0.0002133  (350.3)2 
=  0.9983  —  0.0101  +  26.17 
=i  27. 1582  Mean  specific  heat. 

Evidently  a  mistake  is  made  in  translating  the  last  term 
of  this  formula  from  its  original  source,  for  it  should  be 
.0000002133  (t  — 32)2.  On  this  basis,  we  have  that 

Cm  =  0.9983  —  0.0101  +  .02617  =  1.0346 
In  the  steam  tables  the  heat  of  liquid  for  382°  is  355.0 
B.  t.  u.  and  for  383°  is  356.1  B.  t.  u.     Hence  the  mean  specific 


284  FUEL  OIL  AND  STEAM  ENGINEERING 

heat  Cm  is  approximately  1.1,  which  indicates  tliat  I  ad  the 
decimal  points  been  carried  further  the  specific  heat  ap- 
proaches that  set  forth  in  the  above  correction. 

Problem  No.  13 — At  a  certain  central  station  there  are 
four  773  boiler  horsepower  Parker  boilers.  These  boilers  were 
used  to  give  a  10,000  kw.  load  at  the  terminals  of  a  turbine 
which  has  an  over-all  efficiency  of  21  per  cent.  What  was 
the  percentage  of  overload  on  the  boilers? 

Solution. 

10000 

—  =  47,600  kw.  actually  taken  from  boilers 

.21  (neglecting  losses  in  steam  mains) 

Since  1  hp.  =  .746  kw. 

47600 

—  —  63,800    mechanical    horsepower    actually    taken    off 
.746  boilers. 

From  discussion  in  text,  we  have 

34.5  X  970.4  X  777.5 

-  =  13.14  =  ratio  of  boiler  horsepower  to 
60  X  33000  mechanical  horsepower. 

63,800 

.'.  -        -  =  4850  Bl.  h.  p.  actually  taken  from  boiler. 
13.14 

4  X  773  =  3092  Bl.  h.  p.  rated  capacity. 

4850—3092 

.-.  -  -  X  100  =  56.8%  overload. 

3092 

Problem  No.  14 — A  Parker  boiler  under  test  operated 
with  the  following  conditions:  Steam  pressure  179.7  Ibs. 
gage;  temperature  of  feed  water  entering  boiler  was 
123.4°  F.;  barometer  for  the  day  read  30.1  inches  of  mercury. 

Find  the  factor  of  evaporation  for:  (a)  steam  super- 
heated 182°  F.;  (b)  dry  superheated  steain;  and  (c)  5%  wet 
steam. 

Solution. 
30.10  X 

=  -       -  or  X  =  14.78  Ib.  per  sq.  in.  atmosp!  eric  read- 

29.92          14.696  ing  of  day. 

Gage  reading =  179.7     pounds 

Atmospheric  pressure    =     14.78  pounds 

.'.  Abs.  pressure  of  boiler =  194.48  pounds 


ILLUSTRATIVE  PROBLEMS  285 

From  Steam  Tables: 

hj   =  heat  of  liquid  at  absolute  boiler  pressure..  r=    352.45 
L!  =  latent  heat  of  evaporation  at  absolute  boiler 

pressure   =     845.2 

H!  =!  total  heat  of  steam  at  absolute  pressure...  =  1197.65 
h2   =  heat  of  liquid  at  temperature  of  entering 

feed  water =      91.3 

Hs  =  total  heat  of  superheated  steam  (194.48  Ib. 

pressure  and  182°   superheat) =  1297.99 

X    =  quality  of  steam  =          .95 

Hs  — h2         1297.99  —  91.3        1206.69 

(a)  Fe  =  -  =        1.243 

970.4         970.4       970.4 

Hj  — h2    1197.65  —  91.3   1106.35 

(b)  Fe  =  -  —    1.141 

970.4  970.4  970.4 


„!— ha          352.45+.95X845.2— 91.3 
(c)   Fe  =  - 

970.4  970.4 

1065.25 


=        1.097 


970.4 

Problem  No.  15  —  In  a  boiler  test,  the  temperature  of 
the  feed  water  entering  the  boiler  was  170.7°  F.,  the  steam 
pressure  was  144  pounds  gage,  and  the  barometer  read  29.28 
inches  of  mercury. 

Find  the  factor  of  evaporation  for:  (a)  dry  saturated 
steam;  (b)  10  per  cent  wet  steam;  (c)  steam  superheated 
125°  F. 

Solution. 

29.28  X  29.28 

-  or  X  = X  14.696  =  14.38  Ibs.  per  sq.  in 

29.92       14.696  29.92  atmospheric 

pressure. 
Boiler  gage  reading      =:  144.       Ib. 

Atmospheric  pressure   =    14.38  Ib. 


.'.  Abs.  boiler  pressure  =  158.38  Ib.  per  sq.  in. 

From  Steam  Tables: 

hj   =  heat  of  liquid  at  absolute  boiler  pressure. .  —    334.7 
L,  =  latent  heat  of  evaporation  at  absolute  boiler 

pressure =    859.6 


286  FUEL  OIL  AND  STEAM  ENGINEERING 

Hj  =  total    heat    of    steam    at    absolute     boiler 

pressure    .............................  =  1194.34 

h,>   =  heat    of    liquid  at    temperature  of  entering 

feed  water  ...........................  =    138.57 

HS  =•  total  heat  of  superheated  steam  (158.38  Ib. 

pressure  and  125°  superheat)  ..........  =  1263.88 

H,—  h,        1194.34—138.57       1055.77 

(a)  Pe  =  -  1.08S 

970.4         970.4       970.4 


,—  h3         334.7+.90X859.6—  138.57         969.13 

(b)  F,  —  - 

970.4  970.4  970.4 

=  .999  (where  X  =  quality  of  steam) 

Hs  —  h,        1263.88—138.57       1125.31 

(c)  F,  =  -  1.159 

970.4  970.4  970.4 

Problem  No.  16  —  What  is  the  equivalent  evaporation  in 
Ib.  of  water  per  hr.  from  and  at  212°  F.  if  the  water  fed  to  a 
boiler  has  a  total  weight  of  64494  Ib.  and  the  factor  of  evapo- 
ration is  1.193  Ib.? 

Solution. 

By  applying  the  fundamental  formula  developed  in  the 
text,  we  have  at  once  equivalent  evaporation  from  and  at 

212°   F.  =  64494  X  1.193  =  76950  Ibs.    " 

Problem  No.  17  —  Compute  the  factor  of  evaporation  for 
a  boiler  generating  dry  saturated  steam  under  a  pressure  of 
98.1  Ib.  per  sq.  in.  abs.  and  receiving  its  feed  water  at 
58.8°  F. 

Solution. 

Total  heat  of  saturated  steam  at  98.1  Ibs.  abs.  =  1186. 

Heat  of  liquid  at  temperature  58.8°  F.  =  26.88 

1186  —  26.88 

.'.  Fe  =  -  -  =  1.193 

970.4 

Problem  No.  18  —  What  is  the  weight  of  equivalent  water 
evaporated  to  dry  steam  from  and  at  212°  F.,  if  the  total 
weight  of  water  actually  evaporated  is  53,688  Ibs.  and  the 
factor  of  evaporation  is  1.193? 


ILLUSTRATIVE  PROBLEMS  287 

Solution. 

Weight   of   equivalent   water   evaporated   to    dry   steam 

from  and  at  212°  F.  =  53688  X   1.193  =  64,150 

Problem  No.  19 — The  equivalent  evaporation  of  a  boiler 
under  test  is  5940  Ibs.  of  water  per  hour,  and  the  total  heating 
surface  of  the  boiler  is  found  to  be  2031  sq.  ft. 

What  is  the  average  equivalent  evaporation  per  sq.  ft. 
of  water  heating  surface  per  hour? 

Solution. 

The  average  equivalent  evaporation  per  sq.  ft.  of  water 
heating  surface  per  hour  is  evidently 

5940 

-  =  2.93 
2031 

Problem  No.  20— The  equivalent  evaporation  of  a  boiler 
under  test  is  found  to  be  5940  Ib.  of  water  per  hour. 
\Vhat  is  the  boiler  horsepower  of  the  boiler? 

Solution. 

By  definition 

5940 

Bl.  H.  P.  —        -  =  172.2 
34.5 

Problem  No.  21— The  rated  horsepower  of  a  boiler  is 
given  by  the  builders  as  210  Bl.  h.  p.  Under  test  172.2  Bl.  h.  p. 
were  actually  developed. 

What  was  the  percentage  of  boiler  capacity  developed? 

Solution. 

Capacity  of  boiler  as  developed  in  percentage  is 

172.2 

X    100  —  82% 


210 

Problem  No.  22 — What  is  the  equivalent  evaporation  per 
Ib.  of  coal  as  fired  in  a  boiler  under  test  when  the  weight  of 
equivalent  water  evaporated  to  dry  steam  from  and  at  212° 
F.  is  64150,  and  the  total  weight  of  fuel  consumed  as  fired  is 
8012? 

Solution. 
Equivalent  evaporation  per  Ib.  of  coal  as  fired  = 

64150 

-  =  8.00 
8012 


288  FUEL  OIL  AND  STEAM  ENGINEERING 

Problem   No.  23 — From  a  Parker  boiler  test  covering  a 
period  of  8  hrs.,  the  following  data  were  taken: 

Steam  pressure  (gage)  185.3  Ib.  per  sq.  in. 

Atmospheric  barometer 30.2  in. 

Temp,  of  water  entering  the  boiler 169.1°  F. 

Temp,    of   steam   leaving   the    superheater 

drum 527.°  F. 

Specific  gravity  of  the  oil  at  60°  F 9705 

Percentage  of  water  in  the  oil 7  of  1  % 

Calorific  value  of  oil  per  Ib 18,752  B.  t.  u. 

Weight  of  oil  as  fired 15,084  Ib. 

Total  weight  of  water  fed  to  boiler. 205,277  Ib. 

What  is  the  degree  of  superheat  of  the  steam  leaving  the 
superheater? 
Solution. 

30.2 

Barometer  reading  =  30.2  in.  or  -  =  14.83  Ib.  per  sq  in. 

2.036 

Steam  pressure  abs.  =  185.3  +  14.83      =  200.13  Ib.  per  sq.  in. 
From  tables  tx  =  381.9° 

Temp,  of  steam  leaving  superheater  drum  =  527°  F. 
.'.   527  --  381.9  =  145.1°   superheat 

Problem   No.  24.— What  is  the  gravity  of  the  oil  in  de- 
grees Baume  in  Problem  23? 

Solution. 

For  light  liquids: 

140 
Sp.  gr.  =  - 

130  +  Deg.  Baume 

140 
.9705  =3  


130  +  Deg.  Baume 
.9705  (Deg.  Baume)  =  HO  — 130  X  .9705 

140  —  130  X  .9705 
.'.     Deg.  Baume  == : 


.9705 
13.84 


—  14.26 


.9705 

Problem  No.  25— What  is  the  weight  of  the  oil  corrected 
for  moisture  in  Problem  23? 


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ILLUSTRATIVE  PROBLEMS  289 

Solution. 

Percentage  of  water  in  the  oil  —  .7  of  1% 

Wt.  of  oil  as  fired =  15,084  Ib. 

/.  15,084  X   .007  =  105.6  Ib.  =  Wt.  of  water  in  oil 
Weight  of  oil  corrected  for  moisture  = 

15,084  —  105.6  =  14,978.4  Ib. 

Problem    No.  26 — What  is  the  factor  of  evaporation  in 
Problem  23? 

Solution. 

Hs  — h2 

Factor  of  evaporation  =  —  -  (for  superheated  steam) 

970.4 

From  problem  23,  P1  =  200.13  Ib.  per  sq.  in.  and  145.1°  super- 
heat.   • 

.'.  From  tables  Hs  =  1280.1  B.  t.  u. 
Also  from  problem  23  P2  =  14.83  Ib.  per  sq.  in. 

.'.  From  tables  h,  =  136.96  B.  t.  u. 

1280.1  —  136.96 
Factor  of  evaporation  =  — 

970.4 

=  1.178 

Problem    No.  27 — Determine  the  equivalent  evaporation 
from  and  at  212°  F.  from  Problem  23. 

Solution. 

Total  wt.  of  water  fed  to  boiler  =  205,277  Ib. 

Duration  of  test =  8  hrs. 

Equivalent  evaporation  —  Water  evaporation  per  hr. 

X  factor  of  evaporation  = 

205,277 

-   X    1.178  —  30227  Ib. 
8 

Problem    No.  28 — What  is  the  boiler  horsepower  devel- 
oped in  A.  S.  M.  E.  rating  in  Problem  23? 

Solution. 

Equivalent  evaporation  from  and  at  212°  F. 
H.  P.  —  - 

34.5 

30227 

-  =  876 
34.5 


290  FUEL  OIL  .AND  STEAM  ENGINEERING 

Problem    No.   29 — What   is    the    equivalent    evaporation 
from  and  at  212°  F.  per  Ib.  of  oil  as  fired  in  Problem  23? 

Solution. 
Wt.  of  oil  as  fired  =  15,084  Ib. 

15,084 

Wt.  of  oil  as  fired  per  hr.  —  -       -  —  1,885.5  Ib. 

8 

Equivalent  evaporation  =  30,227 

Equivalent  evap.  from  and  at  212°  per  Ib.  of  oil  as  fired 

30,227 

-  16.03  lb.- 


1,885.5 

Problem  No.  30 — What  is  the  equivalent  evaporation 
from  and  at  212°  F.  per  Ib.  of  oil  corrected  for  moisture  in 
Problem  23? 

Solution. 

Wt.  of  oil  corrected  for  moisture  =  14,978.4  Ib. 
Wt.  of  oil  corrected  for  moisture  per  hr.  — 

14,978.4 

—    _L,o<^.o    ID. 


Equiv.  evap.  from  and  at  212°  per  Ib.  of  oil  corrected 
for  moisture  =: 

30,227 
— =  16.144  Ib. 


1,872.3 

Problem  No.  31 — What  is  the  efficiency  of  the  boiler  in 
Problem  23? 

Solution. 

Ht.  abs.  by  boiler  per  unit  of  time 
Boiler  eff.  = 


Ht.  in  fuel  fed  to  furnace  per  unit  of  time 
30,227  X  970.4 


1872.3  X  18,752 


=  83.29% 


Problem  No.  32 — Assuming  the  steam  was  just  saturated 
and  not  superheated  in  the  above,  what  would  be  the  factor  of 
evaporation  in  Problem  23? 


ILLUSTRATIVE  PROBLEMS  291 

Solution. 

H,—  h, 

Factor  of  evaporation  -  (for  saturated  steam) 

970.4 

From  Problem  23             Px  =  200.13  Ib.  per  sq  in. 

P2  =  14.83  Ib.  per  sq  in. 

From  Tables                    H,  =  1198.1  B.  t.  u. 

h2  —  136.96  B.  t.  u. 

1198.1  —  136.96 
.'.   Factor  of  evaporation  =  - 

970.4 

1061.14 

-  1.093 
970.4 

Problem    No.   33— Assuming   the   steam   to   be   97%    dry, 
what  would  be  the  factor  of  evaporation  in  Problem  23? 

Solution. 

D!  +  XLj  —  h2 

Factor  of  evap.       =  -  -  (wet  steam) 

970.4 

From  Prob.  23,  Px  =  200.13  Ib.  per  sq  in. 
P2  =     14.83  Ib.  per  sq.  in. 
From  tables        ha  —  heat  of  liquid  at  200.13  Ib.  per  sq.  in. 

=  354.9  B.  t.  u. 
h2  =  heat  of  liquid  of  entering  feed  water 

r=  136.96  B.  t.  u. 
Lj  —  latent  heat  of  evap.  at  200.13  Ib  per  sq.  in. 

=1  843.2  B.  t.  u. 
X  =  %  dry  steam  =  .97 

354.9  +  .97  X  843.2  —  136.96 
Factor  of  evap.     =  - 

970.4 

354.9  +  817.9  —  136.96 


970.4 
1035.84 


970.4 


=  1.068 


APPENDIX  II 
Conclusions  and  Recommendations  on  Petroleum 

During  recent  months  considerable  investigation 
has  been  made  looking  toward  conservation  of  fuel.  In 
California,  Governor  W.  D.  Stephens  appointed  a 
notable  committee  consisting  of  Max  Thelen,  who  is 
president  of  the  California  Railroad  Commission, 


as  chairman,  David  Folsom,  professor  of  mining  at 
Stanford  University  and  Pacific  Coast  fuel  adminis- 
trator, and  Eliot  Blackwelder,  professor  of  geology  at 


292 


PETROLEUM  REPORT  293 

the  University  of  Illinois,  in  order  that  a  study  might 
be  made  of  the  conservation  of  fuel  in  the  West. 
During  the  latter  part  of  1917,  this  committee  made 
an  exhaustive  report  and  dealt  with  the  situation  in  a 
masterly  manner.  So  important  are  its  findings,  that 
the  conclusions  and  recommendations  of  this  commit- 
tee are  here  reproduced  in  full : 

I.     CONCLUSIONS 
1.    Utilization. 

Far  beyond  the  borders  of  California,  her  petroleum  and 
its  products  play  a  vital  part  in  commerce  and  industry. 

California  fuel  oil  operates  the  Panama  Canal;  the  great- 
er part  of  the  steam  railroads  of  Washington,  Oregon,  Califor- 
nia, Nevada,  Utah,  Arizona  and  New  Mexico;  the  steamship 
lines  along  the  Pacific  Coast  from  Mexico  to  Alaska  and  across 
the  ocean  to  Hawaii;  the  artificial  gas  plants  of  California, 
Oregon,  Washington,  Nevada,  Arizona  and  Hawaii;  the  mines 
and  smelters  of  California,  Nevada  and  Arizona;  the  cement 
plants  and  sugar  refineries  of  California;  and  a  substantial 
portion  of  the  manufacturing,  industrial  and  agricultural  en- 
terprises of  the  Pacific  Coast  States  of  the  Union. 

California  fuel  oil  supplies  the  Pacific  Coast  fuel  re- 
quirements of  the  United  States  Navy  and  Army  and  of  the 
various  state  and  municipal  governments. 

Radiating  from  California,  north,  west  and  south,  Cali- 
fornia fuel  oil,  to  a  considerable  extent,  operates  the  railroads 
and  industries  of  western  Canada;  the  sugar  refineries  and 
railroads  of  Hawaii;  and  the  railroads,  steamship  companies, 
mines  and  smelters  of  the  west  coast  of  Central  and  South 
America. 

The  products  of  California  petroleum,  such  as  kerosene, 
gasoline,  distillates,  lubricants  and  road  oils,  meet  the  require- 
ments of  Arizona,  California,  Nevada,  Oregon,  Washington, 
Alaska  and  Hawaii.  California  kerosene  is  shipped  in  enor- 
mous quantities  to  China,  Japan,  India  and  Australia,  and  to 
the  western  coast  of  Central  and  South  America.  California 
distillates  and  lubricants  are  sold  in  nearly  every  important 
state  of  the  United  States,  as  well  as  in  England,  Canada  and 
Australia. 

Important  as  is  the  part  which  California  petroleum  and 
its  products  have  heretofore  played  in  the  industrial  life  of 
the  nation  during  times  of  peace,  much  more  important  is  the 
part  which  the  state  should  play  and  will  play,  if  possible,  in 


294 


FUEL  OIL  AND  STEAM  ENGINEERING 


meeting  the  emergency  in  the  simply  of  fuel  oil, 
lubricants,  create.d  by  the  war. 


and 


,'  2.    Production 

California  produces  between  one-fourth  and  one-fifth  of 
the  world's  supply  of.  petroleum.  One-third  of  the  entire  sup- 
ply of  the  United  States  is  produced  in  California. 

The  year  of  California's  greatest  production  was  1914,  in 
which  year  103,620,000  barrels  were  produced.  Production  fell 
in  1915,  to  89,570,000  barrels,  and  increased  slightly  in  1916  to 
91,820,000  barrels. 


Graphical  Display  of  Petroleum  Production 


•Notwithstanding  the  fact  that  a  net  average  of  52  new 
wells  was  added  to  the  producing  wells  of  California  during 
each  month  from  January  to  May,  1917,  inclusive,  and  the  fact 
.that  drilling  during  these  months  was  more  active -thAn  during 
any  other  period  in  the  last  three  or  four  years,  the  daily  pro- 
duetion  was  slightly  less  in  May  than  in  January. 


PETROLEUM  REPORT  295 

Unless  the  measures  hereinafter  recommended  ftir  in- 
creasing production  are  adopted,  it  is  improbable  that  the  pro- 
duction in  1917  will  exceed  the  1916  production  by  more  than 
2,000,000  barrels,  if  at  all. 

From  the  data  available  to  us,  we  are  convinced  that 
the  public  can  not  hope  for  further  substantial  increases  in 
California's  annual  petroleum  supply  by  the  discovery  of  im- 
portant new  fields  or  of  large  extensions  of  existing  fields. 

3.    Consumption 

The  consumption  of  California  petroleum  in  1916  was 
104,930,000  barrels,  being  more  than  13,100,000  barrels  greater 
than  the  production.  The  excess  was  taken  from  storage. 

Consumption  in  1916  outran  production  an  average  of 
1;100,000  barrels  per  month  and  35,650  barrels  per  day. 

During  the  first  five  months  of  1917,  consumption  outran 
production  5,415,000  barrels,  being  1,083,000  barrels  per  month 
and  35,860  barrels  per  day. 

Due  to  normal  increase  in  consumption  as  well  as  the  ad- 
ditional extraordinary  requirements  of  the  war  which  are  al- 
ready being  felt,  it  is  doubtful  whether  consumption  in  1917 
can  be  reduced  below  the  consumption  of  1916,  notwithstand- 
ing the  substitution  of  other  fuel  for  power  and  the  further 
possibilities  of  conservation  pointed  out  in  this  report. 

Consumers  of  California  petroleum  will  shortly  face  a 
condition  of  decreasing  production  and  increasing  demand. 
This  condition  points  inevitably  to  the  necessity  of  develop- 
ing other  sources  of  fuel  or  power. 

4.    Storage 

Crude  oil  stocks  in  California  have  fallen  from  57,147,000 
barrels  on  December  31,  1915,  to  44,036,000  barrels  on  Decem- 
ber 31,  1916,  a  reduction  during  the  year  of  13,110,000  barrels,: 
or  23  per  cent. 

Standard  Oil  Company  reports  that  during  the  first  five 
months  of  1917  the  field  and  pipe  line  crude  oil  stocks  of  all 
companies  were  further  depleted  as  follows: 

Storage  Depletion 
1917 —  in  Barrels. 

January 976,036 

February    1,031,960 

March .         854,333 , 

April 1,197,475       ' 

May     1,355,318 


Total. 5,415,122 

The  total  remaining  storage  on  June  1,  1917,  is  reported 
to  have  been  slightly  in  excess  of  38,000,000  barrels. 


296  FUEL  OIL  AND  STEAM  ENGINEERING 

A  portion  of  the  crude  oil  in  storage  can  not  be  utilized 
because  it  is  located  below  the  outlets  of  tanks  and  reservoirs 
or  Is  being  used  for  the  operation  of  oil  pipe  lines  or  for  other 
reasons.  Of  the  total  stocks  on  June  1,  1917,  not  in  excess 
of  32,000,000  barrels  were  available  for  use.  Of  this  amount, 
12,000,000  barrels  were  refining  oil  and  would  yield  approxi- 
mately 7,000,000  barrels  of  residuum.  On  June  1,  1917,  there 
were  available  from  crude  oil  stocks  approximately  27,000,000 
barrels  for  fuel. 

If  the  present  excess  of  consumption  over  production, 
amounting  to  an  average  of  1,083,000  barrels  per  month,  con- 
tinues, the  entire  available  storage  of  California  fuel  oil  will 
be  exhausted  by  June  1,  1919. 

If  a  margin  of  safety  of  10,000,000  barrels  of  fuel  oil  is 
maintained,  and  if  the  present  relationship  between  produc- 
tion and  consumption  continues,  the  margin  of  safety  for  fuel 
oil  will  be  reached  by  September  20,  1918. 

If  consumption  is  materially  increased,  as  seems  likely, 
both  because  of  normally  increased  requirements,  as  well  as 
the  extraordinary  requirements  of  the  war,  or  if  production 
decreases,  as  seems  likely  unless  the  relief  herein  recom- 
mended is  given,  both  the  margin  of  safety  and  the  complete 
depletion  of  all  California  stocks  will  be  reached  considerably 
prior  to  the  dates  indicated. 

The  principal  railroads  of  California,  with  the  exception 
of  the  Southern  Pacific  Company,  have  made  the  necessary 
arrangements  to  meet  their  requirements  for  at  least  one 
year. 

At  the  present  rate  of  production  by  Kern  Trading  and 
Oil  Company,  the  Southern  Pacific  Company's  fuel  oil  bureau, 
bearing  in  mind  also  the  purchase  of  fuel  oil  by  the  Southern 
Pacific  Company,  including  1,000,000  barrels  bought  from 
Union  Oil  Company  and  not  as  yet  drawn  on,  and  bearing  in 
mind  also  the  Southern  Pacific  Company's  consumption  of 
fuel  oil,  the  Kern  Trading  and  Oil  Company's  storage  of  fuel 
oil  will  be  exhausted  by  December,  1917,  unless  the  recently 
augmented  drilling  operations  of  Kern  Trading  and  Oil  Com- 
pany increases  the  Southern  Pacific  Company's  production 
and  unless  the  Southern  Pacific  Company  effects  a  substantial 
saving  of  fuel  oil  by  converting  to  coal  those  portions  of  its 
•  system  which  are  located  in  proximity  to  the  coal  fields  of 
Washington,  the  Rocky  Mountain  States  and  New  Mexico.  If 
the  receipts  of  fuel  oil  by  the  Southern  Pacific  Company  de- 
crease or  its  consumption  increases,  the  depletion  of  its  stocks 
will  occur  before  December  1,  1917. 


PETROLEUM  REPORT 


297 


If  the  Kern  Trading  and  Oil  Company's  storage  should 
be  exhausted,  it  would  be  necessary  for  Southern  Pacific  Com- 
pany to  enter  the  market  to  purchase  oil  from  general 
stocks  in  storage,  which  amounted  on  June  1,  1917,  to  slightly 
over  38,000,000  barrels.  These  stocks  are  owned  principally 
by  Standard  Oil  Company  and  Union  Oil  Company.  If  these 
companies  should  be  unwilling  to  sell  to  the  railroads  fuel  oil 
from  their  storage,  we  assume  that  the  federal  government 
would  have  the  right  to  commandeer  the  stocks  and  to  compel 
their  delivery  for  the  operation  of  the  railroads  as  long  as  the 
stocks  hold  out.  Such  action,  if  on  a  large  scale,  would  neces- 
sarily deprive  other  important  industries  of  petroleum  and  its 
products. 

5.    Conservation 

Field  losses  of  petroleum  in  the  California  fields  have 
been  almost  entirely  eliminated  and  the  amount  of  fuel  oil 
used  in  field  drilling  and  pumping  has  been  largely  reduced 


Diagramatic  Representation  of  Refining  the  Product 

by  the  substitution  of  natural  gas  and  electric  energy.  The 
operators  are  now  generally  taking  steps  to  reduce  the  re- 
maining use  of  approximately  8500  barrels  of  fuel  oil  daily  by 
the  installation  of  jacks  and  electric  motors.  The  use  of  fuel 
oil  in  the  fields  for  pumping  and  drilling  can  not  be  entirely 
eliminated. 

The    principal    petroleum    refineries   of    California  are 
working  on  improved  processes  of  refining.     The  amount  of 


2.98 


FUEL  OIL  AND  STEAM  ENGINEERING 


crude  oil  which  is  being  refined  is  increasing  and  a  propor- 
tionally larger  amount  of  gasoline  and  lubricants  is  also  being 
secured.  The  result  has  been  a  large  surplus  of  kerosene 
which  it  has  been  necessary  to  export  to  the  Orient,  Australia 
and  Central  and  South  America. 

Mexican  petroleum  was  substituted  early  in  1917  for  Cal- 
ifornia petroleum  amounting  to  approximately  2,750,000  bar- 
rels annually,  heretofore  sold  by  Union  Oil  Company  in  Chili. 
A  considerable  portion  of  the  remaining  3,000,000  barrels  of 
California  fuel  oil  sold  in  1916  on  the  west  coast  of  Central 
and  South  America,  including  the  Panama  Canal,  can  like- 
wise be  saved  by  the  substitution  of  Mexican  petroleum  from 
the  fields  of  Tampico  and  Tuxpam.  By  reason  principally  of 


s  ,        Comparison  of  Coal  and  Fuel  Oil  Production 

transportation  difficulties,  Mexican  petroleum  will  not  be 
available,  during  the  war,  as  a  further  substitute  for  more 
•than  3  per  cent  of  California  petroleum.  After  the  termina- 
tion of  the  war  and  the  resumption  of  normal  transportation 
conditions,  we  may  assume  that  Mexican  petroleum  will  play 
an  important  part  in  the  commerce  and  industry  of  a  consid- 
erable portion  of  the  Pacific  coasts  of  North,  Central  and 
South  America. 

Coal  can  not  be  substituted  for  California  fuel  oil  to  any 
substantial  extent  during  the  war  because  of  present  difficul- 
ties in  the  production  and  transportation  of  coal.  Approxi- 
mately 1,000,000  barrels  of  California  fuel  oil  will  be  saved 


PETROLEUM  REPORT  299 

in  the  ensuing  year  in  the  Northwest  by  the  substitution  of 
coal  for  California  fuel  oil  by  the  Oregon  Short  Line  and  other 
industries.  The  Los  Angeles  and  Salt  Lake  Railroad  Com- 
pany and  The  Western  Pacific  Railroad !  Company  are^  con- 
verting a  portion  of  their  systems  in  Utah  and  Nevada  from 
California  fuel  oil  to  coal  produced  in  the  Rocky  Mountain 
States.  The  Southern  Pacific  Company  and  the  Atchison, 
Icpeka  and  Santa  Fe  Railway  Company  can  also  gradually 
convert  from  fuel  oil  to  ccal  those  portions  of  their  systems 
which  are  in  proximity  to  the  coal  fields  of  the  Northwest,  the 
Rocky  Mountain  States  and  New  Mexico.  Apart  from  what 
has  already  been  accomplished  and  the  further  possibilities 
herein  indicated,  there  is  little  possibility  of  further  conver- 
sion from  California  fuel  oil  to  coal  during  the  war,  unless  the 
conditions  surrounding  the  production  and  transportation  of 
coal  materially  change. 

Powdered  coal  has  been  successfully  used  in  cement 
plants,  stationary  boilers  or  power  plants ,  and  metallurgical 
furnaces.  One  cement  plant  in  the  Northwest  has  recently 
converted  its  plant  from  California  fuel  oil  to  powdered  coal, 
resulting  in  a  saving  of  84,000  barrels  of  California  fuel  oil 
annually.  Apart  from  a  possible  slight  additional  saving  in 
the  Northwest,  it  is  not  reasonable  to  expect  that  powdered 
coal  will  be  further  substituted  for  California  fuel  oil -during 
the  war. 

Hydro-electric  energy  has  already  been  substituted  to  a 
considerable  extent  for  California  fuel  oil  in  industrial  and 
agricultural  uses,  but  the  difficulty  in  securing  copper  aiid 
other  material  and  the  disturbance  of  existing  conditions  are 
such  that  large  additional  savings  of  California  fuel  oil  by 
the  substitution  of  hydro-electric  energy  can  not  be  antici- 
pated during  the  war.  A  small  saving  of  California  fuel  oil 
can  be  effected,  during  the  war,  by  the  further  substitution  of 
electric  motors  for  fuel  oil  in  the  California  oil  fields  and  by 
such  interconnection  between  the  systems  of  various  electric 
companies  as  will  eliminate  or  reduce  the  necessity  of/ main- 
taining steam  electric  plants.  After  the  termination  of  the 
war  and  the  restoration  of  normal  industrial  conditions,  we 
may  expect  that  hydro-electric  energy  will  play  an  increas- 
ingly important  part  as  a  substitute  for  fuel  oil  in  all ;  the 
Pacific  Coast  States  in  which  such  energy  is  available. 

Natural  gas  has  already  been  substituted  to  almost  the 
entire  extent  of  its  supply,  for  fuel  oil  in  the  California 
petroleum  fields,  and  for  fuel  oil  and  artificial  gas  for  higher 
industrial  and  domestic  uses.  The  maximum  production  of 


300 


FUEL  OIL  AND  STEAM  ENGINEERING 


natural  gas  in  the  California  petroleum  fields  has  been  reached 
and  it  is  not  to  be  anticipated  that  natural  gas  will,  to  any 
substantial  extent,  further  replace  other  forms  of  fuel. 

We  conclude  that  during  the  war  some  further  saving 
of  California  fuel  oil  is  possible  by  elimination  of  losses  and 
substitution  of  other  forms  of  fuel  or  power,  but  that  no 


Comparative  Uses  of  Crude  Petroleum 

large  saving  can  be  effected  without  very  serious  impairment 
to  the  efficiency  of  the  transportation  systems  and  industries 
of  the  Pacific  Coast. 

The  great  importance  of  gasoline  and  lubricants  must  be 
recognized  and  steps  should  be  taken  as  soon  as  reasonably 
possible  to  the  end  that  no  more  unrefined  petroleum  is 
burned  by  any  railroad  company  or  other  industry.  No  part  of 
California-  petroleum  should  be  thus  burned  except  the 
residuum  left  after  refining. 

If  a  sufficient  amount  of  fuel  oil  can  not  be  secured  from 
Mexico  after  the  war,  the  railroads  and  other  industries  of 
the  Pacific  Coast  must  gradually  make  arrangements  to  use 
other  forms  of  energy,  such  as  hydro-electric  energy  or  pow- 
dered coal. 

6.    The  Remedy 

The  remedy  which  imperatively  presents  itself  in  view 
of  the  emergency  created  by  the  war  is  the  prompt  and  sub- 
stantial increase  in  the  production  of  California  petroleum. 

While  we  do  not  desire  to  minimize  the  results  which 
can  be  accomplished  and  should  be  accomplished  by  the  fur- 
ther diminution  of  field  losses,  the  higher  use  of  petroleum 
and  its  products  and  the  substitution  of  other  forms  of  fuel 
or  power,  during  the  war  as  well  as  thereafter,  the  cardinal 
fact  remains  that  the  only  means  which  will  be  effective  in 
a  large  way  to  meet  the  present  emergency  is  a  prompt,  sub- 
stantial increase  in  production. 

We  estimate  that  this  increased  production  should 
amount  to  more  than  30,000  barrels  per  day,  and  that  such  in- 


PETROLEUM  REPORT  301 

creased   production   can  not  reasonably  be   expected   before 
June  1,  1918. 

Each  difficulty  standing  in  the  way  of  prompt  and  sub- 
stantial increased  production  must  be  quickly  solved,  if  the 
increase  is  to  forestall  a  serious  industrial  crisis. 

7.    Increased   Production — Material 

The  necessary  increased  production  can  not  be  secured 
unless  large  additional  amounts  of  oil  well  casing,  drill  stem 
pipe  and  other  oil  well  material  are  promptly  brought  into 
California. 

The  oil  well  supply  houses  report  that  they  can  fill  no 
orders  for  complete  drilling  outfits  in  addition  to  those  already 
taken. 

The  larger  oil  companies  have  on  hand  or  have  hereto- 
fore placed  orders  for  enough  material  to  complete  their  1917 
drilling  operations  as  heretofore  planned,  but  no  material  for 
additional  drilling  beyond  such  plans.  Many  small  operators 
report  that  they  would  drill  if  they  could  secure  the  necessary 
material,  but  that  it  has  been  impossible  for  them  to  secure 
such  material,  even  at  the  high  prices  now  prevailing. 

Receiver  Payne  reports  that  he  is  willing  to  drill,  if 
authorized  by  the  federal  court,  but  that  he  does  not  know 
where  he  could  secure  the  necessary  material  unless  the  fed- 
eral government  should  take  the  necessary  steps  to  assist  the 
California  producers. 

In  our  opinion,  the  only  way  to  meet  the  situation,  in 
view  of  the  existing  conditions,  is  to  have  the  federal  gov- 
ernment direct  the  manufacturers  of  oil  well  supplies  to  de- 
vote sufficient  capacity  of  their  plants  to  supply  the  require- 
ments of  oil  producers  in  California  and  other  sections  of 
the  United  States,  and  to  direct  the  railroads  to  transport  such 
supplies  promptly. 

8.    Increased  Production — Labor 

Over  80  per  cent  of  the  laborers  who  are  employed  in 
the  oil  fields  and  refineries  are  skilled  men,  most  of  whom 
it  would  be  difficult  to  replace.  If  any  considerable  number  of 
these  men  are  taken  from  their  present  employment  it  will  be 
impossible  to  increase  the  production  of  petroleum  in  Cali- 
fornia, and  difficult  even  to  maintain  the  present  production. 

About  4  per  cent  of  these  men  have  already  left  their 
employment  and  have  volunteered  for  service  in  the  various 
branches  of  the  Army  and  Navy.  About  40  per  cent  of  these 
employees  have  registered  for  the  draft. 

We    suggest   the    advisability   of   drawing   this    situation 
to  the  attention  of  the  federal  government. 


J-. 


"III 

be 

T3   C   K 


PETROLEUM  REPORT  303 

9.    Increased  Production — The  Land 

In  order  to  secure  an  increase  of  30,000  barrels  per  day 
in  the  production  of  California  petroleum,  drilling  must  be 
done  on  the  land  which  will  yield  the  largest  production  in 
the  shortest  time  by  the  expenditure  of  the  smallest  amount 
of  drilling  material  and  labor. 

In  Chapter  X  of  this  report  we  have  presented  the 
salient  facts  regarding  the  productivity  of  the  petroleum  lands 
of  the  state,  together  with  our  conclusions  as  to  where  the 
land  most  available  for  prompt  increased  production  is  lo- 
cated. We  conclude  that  such  lands  are  located  in  order  of 
productivity,  with  due  regard  to  time  and  economy  of  drilling 
material,  in  (1)  the  Buena  Vista  Hills  (Midway  field),  (2)  the 
Coyote  Hills  and  La  Merced  fields  (Whittier-Fullerton  field) 
(3)  the  Sunset  field,  and  (4)  the  East  Coalinga  field. 

Of  the  most  desirable  undrilled  lands,  approximately  70 
per  cent  are  involved  in  litigation  with  the  federal  govern- 
ment. Nearly  one-half  of  the  best  undrilled  proved  petroleum 
lands  of  the  state  are  claimed  by  Kern  Trading  and  Oil  Com- 
pany, the  fuel  oil  bureau  of  the  Southern  Pacific  Company, 
under  patents  heretofore  issued  to  Southern  Pacific  Railroad 
Company.  Of  the  remaining  lands  in  litigation,  a  part  of  the 
most  productive  undrilled  land  is  in  the  possession  of  Howard 
M.  Payne,  federal  receiver. 

The  most  promising  land  in  the  Coyote  Hills  and  La 
Merced  fields  is  owned  by  Standard  Oil  Company  and  partly 
by  Union  Oil  Company.  This  land  is  not  involved  in  litiga- 
tion. The  wells  in  this  district,  however,  are  much  deeper 
than  in  the  Midway  field  and  the  limits  of  the  productive 
territory  have  not  as  yet  been  thoroughly  proved. 

The  desirable  Buena  Vista  Hills  lands  are  practically  all 
located  in  Naval  Reserve  No.  2.  A  considerable  area,  how- 
ever, of  presumably  productive  undrilled  proved  land,  which 
in  our  judgment  should  be  promptly  and  intensively  drilled, 
is  located  in  the  Sunset  field  and  in  the  east  Coalinga  field. 
The  larger  portion  of  these  lands  is  claimed  by  Kern  Trading 
and  Oil  Company.  A  portion  of  them,  particularly  in  the  Sun- 
set field,  is  in  the  possession  of  the  federal  receiver.  These 
latter  lands,  in  our  judgment,  should  be  promptly  drilled,  not 
merely  because  of  the  large  production  which  can  presumably 
be  secured  therefrom,  but  also  because  water  is  known  to  be 
encroaching  on  them  and  probably  will  ruin  them  in  large 
measure  unless  they  are  promptly  drilled. 

The  oil  companies  which  own  undisputed  patented  lands 
of  presumed  heavy  productivity  are  under  a  grave  responsibil- 


304  FUEL  OIL  AND  STEAM  ENGINEERING 

ity  to  increase  production  in  the  present  emergency.  With 
the  possible  exception  of  one  of  the  large  companies,  we  are 
of  the  opinion  that  these  oil  companies  are  striving  earnestly 
to  meet  this  responsibility.  Some  operators  are  drilling  wells 
which  entail  the  expenditure  of  large  amounts  of  material 
and  labor  for  a  relatively  small  production. 

A  review  of  the  situation  shows  that  the  present  emer- 
gency can  not  be  met  without  the  assistance  of  the  federal 
government. 

We  shall  not  undertake  to  pass  judgment  on  the  broad 
questions  of  governmental  policy  which  might  be  affected  by 
further  intensive  drilling  in  Naval  Reserve  No.  2.  These  ques- 
tions must  be  left  to  the  wisdom  and  the  justice  of  the  fed- 
eral government  when  the  government  is  in  possession  of  all 
the  facts,  among  which  facts  should  be  included  the  past  and 
present  drilling  operations  which  have  been  and  are  now  be- 
ing carried  on  in  this  reserve,  the  effect  of  such  drilling  on 
the  amount  and  availability  of  the  remaining  oil  content  of 
the  reserve,  the  productivity  and  availability  of  the  lands  in 
the  reserve  as  compared  with  all  other  oil  lands  in  .the  state, 
and  the  extent  of  the  present  emergency  as  contrasted  with 
Hhe  possible  future  needs  of  the  nation. 

We  desire,  however,  to  direct  attention  emphatically  to 
the  fact  that  a  considerable  portion  of  proved  productive  ter- 
ritory, hitherto  undrilled,  is  located  outside  of  the  naval  re- 
serves; that  further  development  of  most  of  this  land  has 
been  stopped  by  litigation  with  the  federal  government;  that 
the  policy  of  the  federal  government  which  has  resulted  in 
the  creation  of  Naval  Reserves  Nos.  1  and  2  can  have  no 
possible  application  to  these  lands  which  are  not  claimed  or 
needed  for  the  Navy,  and  that  with  the  help  of  the  federal 
government  substantially  increased  production  can  be  secured 
from  these  lands. 

We  desire,  further,  to  draw  attention  to  the  fact  that 
unless  the  federal  government  can  bring  about  most  radical 
changes  in  the  supply  of  drilling  material,  the  transportation 
of  petroleum  and  the  development  of  the  land,  the  increased 
production  of  over  30,000  barrels  per  day,  which  in  our  judg- 
ment is  necessary,  can  not  be  secured  without  some  addi- 
tional drilling  in  Naval  Reserve  No.  2. 

After  a  careful  review  of  the  entire  situation  and  con- 
ferences with  all  interested  parties,  we  have  reached  the 
following  conclusions  with  reference  to  production  on  the 
lands  now  in  litigation  outside  of  the  naval  reserves: 


PETROLEUM  REPORT  305 

(1)  As  to  the  lands  not  in  the  possession  of  the  federal 
receiver,  being  largely  lands  claimed  by  Kern  Trading  and 
Oil  Company  (Southern  Pacific  Company),  we  conclude  that 
joint  action  should  at  once  be  taken  by  the  federal  govern- 
ment and  the  claimants  to  such  lands  to  petition  the  federal 
court  to  permit  the  claimants  to  drill  intensively  under  some 
equitable  arrangement  by  which  both  the  federal  government 
and  the  claimants  will  be  protected,  the  federal  government 
to  be  protected  as  to  the  value  of  the  petroleum  extracted  in 
case  the  government  should  win  the  litigation  and  the  claim- 
ants to  be  protected  to  the  extent  at  least  of  their  expendi- 
tures incurred  under  such  stipulations  in  case  they  should 
lose  the  litigation. 

(2)  As   to   the  lands   in  the   possession   of  the   federal 
receiver,  we  conclude  that  the  receiver  should  be  promptly 
permitted  or  directed  by  the  federal  court,  of  which  he  is  an 
officer,   to   drill   additional  wells   in   such   territory  as   gives 
promise  of  substantially  increased  production.     If  the  author- 
ity of  the  federal  congress  is  necessary  to  authorize  the  re- 
ceiver to  use  for  this  purpose  funds  now  in  his  hands  or  here- 
after   acquired,  we    conclude    that  the  necessary  legislation 
should  be  speedily  enacted. 

10.  Increased  Production — Transportation 
When  the  conversion  of  the  Standard  Oil  Company's 
six-inch  pipe  line  from  the  Whittier-Fullerton  field  to  the  re- 
finery at  El  Segundo  to  a  ten-inch  line  has  been  completed, 
the  oil  pipe  lines  of  California,  if  properly  administered  and 
correlated,  will  be  sufficient  to  take  care  of  the  pipe  line 
transportation  of  such  increased  production  as  may  reason- 
ably be  anticipated. 

The  legislature  of  California  has  declared  that  oil  pipe 
lines  are  common  carriers  and  are  subject  to  the  jurisdiction 
of  the  Railroad  Commission.  The  question  whether  the  oil 
pipe  line  statutes  are  constitutional  has  been  submitted  to 
the  Supreme  Court  of  the  state  of  California.  If  the  legisla- 
tion is  sustained,  the  Railroad  Commission  will  have  author- 
ity to  supervise  the  oil  pipe  lines  so  that  they  may  be  operated 
to  their  greatest  efficiency  from  the  point  of  view  of  the 
entire  transportation  situation.  If  the  jurisdiction  of  the 
Railroad  Commission  is  not  sustained,  some  other  means  must 
be  provided  so  that  the  oil  pipe  lines  may  be  operated  to  full 
efficiency  in  the  present  emergency. 

A  more  efficient  correlation  of  the  use  of  oil  pipe  lines, 
railroad  tank  cars  and  tank  steamers  would  result  in  the  re- 
lease of  a  considerable  number  of  railroad  tank  cars,  which 


306  FUEL  OIL  AND  STEAM  ENGINEERING 

are  badly  needed  to  serve  the  industrial  needs  of  California 
and  neighboring  states.  Standard  Oil  Company  reports  that 
it  is  3500  tank  cars  short  at  its  refinery  at  El  Segundo,  and 
that  it  is  accordingly  unable  to  fill  urgent  orde  -s  from  the 
copper  mines  of  Arizona. 

Increased  transportation  facilities  may  hereafter  become 
necessary  if  the  oil  fields  of  Southern  California  should  be 
called  upon,  from  their  surplus  production,  to  help  meet  the 
requirements  of  central  and  northern  California  and  other 
territory. 

II.     RECOMMENDATIONS 

We  respectfully  submit  the  following  recommendations: 

Recommendation  No.  1 
Increased  Production 

We  recommend  that  every  reasonable  effort  be  made  to 
increase  the  production  of  California  petroleum  promptly  and 
that  to  this  end  additional  drilling  be  undertaken,  as  quickly 
as  material  and  labor  are  available,  on  the  lands  on  which  the 
largest  additional  production  can  be  developed  in  the  least 
time  and  with  the  smallest  expenditure  of  material  and  labor. 

Recommendation    No.  2 
Decreased   Consumption 

We  recommend  that  every  reasonable  effort  be  made, 
consistent  with  the  maintenance  of  the  efficiency  of  our 
transportation  systems  and  industries,  to  conserve  the  supply 
of  California  petroleum  by  the  diminution  of  field  losses,  the 
higher  use  of  petroleum  and  its  products,  and  the  substitu- 
tion of  other  forms  of  fuel  or  power. 

Recommendation  No.  3 

Presentation  of  Facts  to  Federal  Government 
WTe  recommend  that  the  facts  with  reference  to  the 
California  petroleum  situation,  including  specifically  the  im- 
perative necessity  for  additional  production  and  the  relative 
productivity  of  undrilled  but  proved  lands,  be  presented  to 
the  President  of  the  United  States  and  to  tho  appropriate  de- 
partments of  the  federal  government  and  that  the  federal 
government  be  respectfully  urged  to  render  every  assistance 
which  the  government  can  render  consistent  with  the  highest 
public  interest. 

Recommendation   No.  4 

Oil  Well  Material 

We  recommend  that  the  attention  of  the  federal  govern- 
ment be  respectfully  drawn  to  the  advisability  of  directing 
the  manufacturers  of  oil  well  supplies  to  set  aside  sufficient 


PETROLEUM  REPORT 


307 


capacity  of  their  plants  for  the  production  of  oil  well  casing, 
drill  stems,  wire  cables  and  other  material  to  supply  the 
reasonable  requirements  of  California  and  other  sections  of 
the  United  States  and  of  directing  the  railroads  to  transport 
such  supplies  as  expeditiously  as  is  consistent  with  other 
urgent  requirements. 

Recommendation    No.   5 
Labor 

We  recommend  that  the  attention  of  the  federal  govern- 
ment be  respectfully  drawn  to  the  advisability  of  exempting 
from  service  in  the  armed  forces  of  the  nation  all  skilled 
workmen  employed  in  the  petroleum  industry  and  of  indicat- 
ing to  such  workmen  that  their  highest  present  duty  is  to 
assist  in  the  maintenance  and  development  of  t*  e  petroleum 
industry. 

Recommendation    No.  6 
Lands  in  Litigation  With  No  Receiver 

We  recommend  that  the  federal  government  be  respect- 
fully requested,  in  those  instances  in  which  California  petro- 


"A  GEM  OF  THE  OCEAN"— U.  S.  S.  MICHIGAN 
Economic  specifications  for  the  purchase  of  fuel  oil  by  the  U.  S. 
Navy  are  set  forth  on  page  138.  These  specifications  are  helpful  in 
steam  generation  on  both  land  and  sea.  Careful  study  is  being- 
made  in  California  as  outlined  on  this  page  as  to  how  the  actual 
production  of  petroleum  may  the  best  be  most  efficiently  accom- 
plished for  use  in  the  Navy  and  in  the  industries  of  the  nation 


PETROLEUM  REPORT  309 

leum  lands  now  in  litigation  with  the  federal  government  are 
not  in  the  hands  of  the  federal  receiver,  to  consent,  through 
the  Department  of  Justice,  to  stipulations  under  which  the 
claimants  will  be  permitted  to  drill  such  lands  intensively 
under  an  arrangement  by  which  the  federal  government,  if 
it  ultimately  wins  the  suits,  will  be  protected  with  reference 
to  the  petroleum  thus  produced,  and  the  operators  will  be  pro- 
tected, if  they  lose  the  suits,  out  of  the  proceeds  of  the  petro- 
leum thus  produced  to  the  extent  of  at  least  their  expendi- 
tures reasonably  and  fairly  made  under  the  stipulation. 

Whether  any  additional  drilling  shall  be  dene  on  lands 
in  Naval  Reserve  No.  2,  is  a  matter  which  must  be  left  to 
the  wisdom  and  fairness  of  the  federal  government,  when 
the  government  has  before  it  all  the  facts,  including  the 
needs  of  the  government,  present  and  future,  the  extent  and 
the  effect  of  the  past  and  present  production  in  this  reserve, 
the  urgent  necessity  for  increased  production  of  California 
petroleum,  the  relative  productivity  and  availability  of  un- 
drilled  proved  lands,  and  the  fact  that  on  any  reasonable 
assumption  an  additional  production  of  more  than  30,000  bar- 
rels per  day  can  not  be  secured  unless  some  additional  drill- 
ing is  done  in  Naval  Reserve  No.  2. 

We  earnestly  recommend,  however,  that  pending  a  de- 
termination as  to  additional  drilling  in  Naval  Reserve  No.  2, 
all  other  California  petroleum  lands  in  litigation  be  at  once 
thrown  open  to  production  under  the  arrangements  herein 
suggested. 

Recommendation  No.  7 
Lands  in  Litigation  in   Possession  of  Receiver 

We  recommend  that  the  federal  government  be  respect- 
fully requested,  in  those  instances  in  which  California  petro- 
leum lands  now  in  litigation  with  the  federal  government  are 
in  possession  of  the  federal  receiver,  to  take  appropriate 
proceedings,  through  the  Department  of  Justice,  so  that  the 
receiver  may  be  authorized  or  directed  to  proceed  at  once 
to  drill  intensively  such  lands  as  are  presumptively  pro- 
ductive, and  particularly  the  lands  which  are  likely  to  suffer 
from  the  infiltration  of  water  unless  drilled. 

If  the  authority  of  congress  is  necessary,  we  recommend 
that  congress  be  respectfully  requested  to  enact  the  necessary 
legislation. 

Recommendation  No.  8 
Legislation  to  Open  Petroleum  Lands 

We  recommend  that  the  federal  government  be  respect- 
fully requested  to  enact  promptly  legislation  by  which  such 


310  FUEL  OIL  AND  STEAM  ENGINEERING 

lands  in  the  public  domain  as  the  federal  government  may 
consider  wise  and  consistent  with  public  interest  will  be 
opened  to  petroleum  development  on  terms  just  and  reason- 
able both  to  the  federal  government  and  to  such  explorers  and 
operators  as  have  heretofore  proceeded  or  may  hereafter  pro- 
ceed in  good  faith  to  the  exploration  and  development  of 
petroleum  lands.  We  suggest  that  the  area  of  the  lands  in 
each  instance  be  sufficiently  large  to  permit  efficient  opera- 
tion. 

We  believe  that  the  establishment  of  a  definite  construc- 
tive policy  in  this  matter  will  have  a  whclesome  and  stimu- 
lating effect  on  the  petroleum  industry  of  California  and  other 
states. 

Recommendation   No.  9 
Transportation 

We  recommend  that  the  railroad,  steamship,  oil  pipe 
line  and  oil  companies  of  California  be  authorized  and  di- 
rected to  take  steps  immediately  to  so  correlate  their  respec- 
tive transportation  facilities  as  to  make  most  available  and 
efficient  every  agency  employed  in  the  transportation  of 
California  petroleum  and  its  products. 

Recommendation  No.  10 
Ultimate  Conservation 

We  recommend  that  as  soon  as  reasonably  possible, 
bearing  in  mind  the  paramount  necessity  of  the  most  effi- 
cient operation  of  our  transportation  systems  and  other  in- 
dustries during  the  emergency  created  by  the  war,  the  further 
burning  of  California  petroleum,  unless  it  has  first  been  re- 
fined, be  prevented,  the  higher  use  of  California  petroleum 
and  its  products  insured,  substitute  forms  of  fuel  or  power 
developed,  and  the  supply  of  California  petroleum  by  the 
most  efficient  use  thereof  conserved. 


APPENDIX    III 

Helpful    Factors   in   Fuel   Oil   Study  and   Conservation 

The  authors  of  this  work  would  feel  unmindful  of  their 
duty  in  setting  forth  the  elements  of  fuel  oil  and  steam  engi- 
neering did  they  not  at  this  time  point  out  to  the  reader  some 
of  the  helpful  factors  that  are  aiding  in  fuel  oil  study  and 
conservation  in  these  days  of  national  emergency. 

First  and  foremost  must  be  mentioned  the  educative  and 
helpful  influence  of  the  universities  and  technical  colleges  of 
the  West — such  as  the  University  of  California  and  Leland 
Stanford  Junior  University.  These  institutions  are  not  only 
prepared  to  train  technical  fuel  oil  specialists,  but  the  eminent 
scientists  and  engineers  upon  their  teaching  staffs  are  con- 
tributing noteworthy  research  data  for  the  upbuilding  of 
efficient  mining  and  utilization  of  this  important  national 
resource.  Under  the  administration  of  Dr.  Benjamin  Ide 
Wheeler,  president  of  the  University  of  California,  a  most 
helpful  department  of  instruction  has  been  added,  known  as 
the  Extension  Division.  With  Ira  W.  Howerth  as  Director, 
the  Extension  Division  is  now  serving  over  three  hundred 
thousand  people  in  the  state  of  California.  Practically  every 
conceivable  educative  aid  is  available  through  this  branch  of 
university  instruction.  All  operators  or  engineers  interested 
in  fuel  oil,  its  uses  and  conservation,  may  for  a  small  fee 
enjoy  this  excellent  service.  The  only  other  requirement  on 
the  part  of  the  applicant  is  that  he  be  thoroughly  in  earnest 
in  undertaking  such  study.  To  get  in  touch  with  this  excel- 
lent service,  a  letter  should  be  addressed  to  Director  of  Ex- 
tension Division,  University  of  California,  Berkeley. 

Another  important  branch  of  service  in  the  conservation 
of  petroleum  is  that  instituted  by  President  Woodrow  Wilson, 
who  has  appointed  Dr.  H.  A.  Garfield  as  national  fuel  ad- 
ministrator. Mr.  Garfield  in  turn  has  appointed  Mark  L. 
Requa  as  oil  administrator.  Mr.  Requa  is  a  mining  engineer 
of  note  and  much  is  expected  of  him  in  helping  to  solve  the 
fuel  situation.  In  the  administration  of  his  work  the  oil  in- 
dustry will  be  left  in  great  measure  to  govern  itself.  Insist- 
ence, however,  will  be  made  upon  the  oil  industry  that  it  main- 
tain fair  and  reasonable  prices  and  that  it  co-operate  to  the 
fullest  extent  in  supplying  most  efficiently  the  products  of 
petroleum  needed  to  meet  the  requirements  of  our  army,  navy 

311 


312  FUEL  OIL  AND  STEAM  ENGINEERING 

and  allies.  Mr.  Requa  has  appointed  an  able  corps  of  assist- 
ants and  much  good  is  bound  to  result  from  his  labors. 

The  California  Railroad  Commission,  under  the  presi- 
dency of  Max  Thelen,  is  doing  excellent  service  in  the 
efficient  handling  of  the  petroleum  situation.  Authorized 
under  the  law  to  regulate  the  public  utilities  as  to  rates  and 
other  matters,  this  commission  is  now  on  its  own  initiative 
working  out  a  scheme  of  interconnection  of  power  companies 
in  the  state  of  California  that  will  do  much  in  conserving  the 
fuel  oil  in  that  industry.  Mr.  Thelen  has  also  served  as  chair- 
man of  the  Petroleum  Commission  of  the  State  Council  of 
Defense.  The  helpful  conclusions  of  this  commission  are  set 
forth  in  full  in  Appendix  II  of  this  work. 

Especial  attention  is  called  to  the  research  investigations 
of  the  United  States  Bureau  of  Mines  and  the  United  States 
Bureau  of  Standards.  Much  of  the  scientific  data  on  fuel  oil 
specifications  and  steam  generation  contained  in  this  work 
have  been  gleaned  from  the  various  publications  of  the  Bureau 
of  Mines,  while  the  standardization  of  thermometers  as 
treated  in  addition  to  many  other  aids  in  scientific  precision 
described,  must  be  accredited  to  the  helpful  work  of  the 
Bureau  of  Standards.  In  discussions  looking  toward  the  pro- 
duction of  petroleum  the  publications  of  the  United  States 
Geological  Survey  are  timely,  as  are  also  the  publications  of 
the  California  State  Mining  Bureau. 

The  Book  on  Steam  of  the  Babcock  &  Wilcox  Boiler 
Works  is  perhaps  the  most  helpful  of  its  kind  in  existence  in 
setting  forth  the  elementary  laws  of  steam  engineering  in  a 
practical  manner,  and  the  authors  are  greatly  indebted  to  it 
for  many  helpful  items  in  the  present  work. 

In  regard  to  current  aids  in  the  technical  press,  the 
only  paper  in  existence  that  devotes  a  regular  department 
to  the  technical  discussion  of  fuel  oil  and  steam  engineering 
is  the  Journal  of  Electricity,  published  in  San  Francisco.  This 
journal  is  now  in  its  thirty-first  year  of  publication  and  is  the 
recognized  authority  on  this  line  of  discussion. 

The  work  of  the  Pacific  Coast  Section,  N.  E.  L.  A.  along 
lines  of  fuel  oil  economy  in  steam  power  generation  has  proven 
most  helpful.  Through  this  means  of  expression  the  great 
power  companies  of  the  West  which  use  oil  as  a  fuel  are  con- 
tributing noteworthy  aids  to  efficient  uses  of  this  product. 

The  American  Society  of  Mechanical  Engineers  and  the 
American  Institute  of  Electrical  Engineers  constitute  the  two 
great  national  societies  of  professional  status  that  are  exceed- 
ingly helpful  in  fuel  oil  study. 


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INDEX 


Abel-Pensky   tester    138 

Absolute       pressure  —  gage 

pressure   24 

Absolute  scale 47 

Absorption  solutions  in  chim- 
ney analysis  207 

Absorption,   total  heat  of....  116 

Acceleration  denned 16 

Accessories,   boiler   114,  117 

Adjuster   for   steam  gage....*29 
Air- 
actual  and  ideal  supply. ..  .225 
ducts  for  furnace  floor....  *107 

quantity  required    Ill,  210 

regulation   of  furnace.  .163,  164 

required,   correction    215 

spacings,  furnace.  *158,*160,*164 

supplied   to  furnace 219 

supply  essential    110 

weight  for  combustion 214 

Alcohol  thermometers   38 

Alloys- 
cup   for  melting *37 

melting  point  of 37 

Altitude  and  latitude,  barom- 
eter corrections    31 

Analysis,   chimney  gas.  .  .203,  275 

Ashpit,    furnace    *276 

Asphalt  base,   petroleum 133 

Atmospheres,   pressure  in.  ...   64 

Atmospheric  baromenter *24 

Atomization — 

apparatus     for    measuring- 
steam    *238 

calibration   of   orifice *239 

flow  of  steam 237 

heat  loss   256,  261 

steam  in   171,  236,  245 

Atomizer  (see  Burner) 
Atwater-Mahler   bomb    fuel 

calorimeter  *194 

Automatic  control  boiler. ..  .*242 

B.  t.  u.  defined. 45 

Babcock  &  Wilcox  boiler.  *10,  126 

back  shot    *173 

front  shot   *172 

marine  type   *124,  ]  25 

Back  shot  burners.  170,  *173,  *175 

Badenhausen  boiler   129 

Barometer — 

atmospheric    *24 

condenser  type    *27 

correction  for  altitude  and 

latitude 31 

correction  of  brass  scale...   29 
correction,    thermometer 

suspension  for *23 

reading,  reduction  of 28 

Barrel   steam  calorimeter. ...   89 

Baume   scale    134 

hydrometers  *176 

in  determining  heat  value.  .192 
readings  and  specific  grav- 
ity   178 


Blow-off  valve    *118 

Boiler -2,  6,   *52 

accessories    117 

B.   &  W.    .  ..*10,   *124,   *125,   126 

Badenhausen   129 

caution    174 

classification    122 

Code  Committee 140 

cooling  and  cleaning 145 

cylinder  oil  kept  out 144 

drum  and  tubes 123 

Edgemoor    129 

efficiency     109,246 

(see  also  Heat  balance) 

Erie  City   129 


*149 
.126 
.146 

.  78 
.277 
.277 
.123 


evaporation  standard 80 

fire  and  water  tube 123 

front,    showing    gage *218 

Heine  type   129 

horizontal  tubular *1.28 

hp.    (see  Boiler  hp.) 
internally    and    externally 

fired 123 

Keeler 129 

low  water  in   143 

marine *124,   *125,   129 

men   for   operating.  . .  .*122,  174 

operation   115 

Parker *18,  127 

plate   (see  Boiler  shell) 

pressure,   internal    

principles  of  construction 
putting  out  of  service.  .. 

rating,   to  compute 

regulation  tests    

report  of  operation 

return    tubular    

room   H4,  140,  143 

Rust 129 

Scotch  marine 125 

sediment  removed   144 

shell    (see   Boiler  shell) 

Stirling  128 

tea-kettle  and  107 

tests  (see  Boiler  tests) 

test  pump,  portable *143 

Thornycroft 13 

torpedo  boat    130 

units,   connecting  up 143 

vertical  and  horizontal 125 

water  circulation   127 

Boiler  horsepower   ...  .72,  73,  *74 

computations   83 

reduction  to  mechanical  hp.  75 
reduction   to  myriawatts ...   77 

Boiler  shell- 
accessories   H4 

bursting  pressure    152,  154 

joints   *151,  *153,  *155 

resistance    to    compression.  151 

resistance  to  shear 150 

riveted  section   151 

safe  pressure   154 

strength   of    147,  148,  149 

Page  numbers  referring  to  illustrations  are  marked  by  an  asterisk  (*) 

314 


INDEX 


315 


..243 


Boiler  Tests    241,269 

beginning  and  stopping.  . .  .244 

boiler  efficiency   246 

chimney  gas  analysis   248 

duration   

efficiency   under   normal 

rating   243 

heat  in  steam  generated... 

instructions   for    243 

log  sheet   for  fuel  oil 

feed 250,  *251 

log  sheet   for  weighing 

water 250 

log  sheet,  general. 251,  *252,*253 

measurement   of  oil 245 

object    242 

observations  necessary  ....  247 

overload 245 

plotting  of  data 254,  *253 

pressure  readings   247 

quick  steam     246 

steam   in   atomization 245 

tabulation 249 

temperature  readings 248 

water  and  oil 229 

weighing  of  water 244 

Bomb  fuel  calorimeter — 

Atwater-Mahler   *194 

Boyle's  law 43,  46 

Brickwork  in  furnace.  .  *158,  *164 
British  thermal  unit,  denned.   45 

Builder's   rating   77 

Bureau  of  Mines,  U.   S.  ..185,  233 

Burner *2,  110 

back  shot   170,  *173,  *175 

cautions   174 

classification 166 

efficiency,  increasing 270 

front  shot 170,  *172,  174 

home-made  type   169,  *170 

inside  mixer  type 166,  *167 

mechanical  atomizer.  .168,  *169 
men  required  for  opera  ting.  174 
outside  mixer  type. . .  .168,  *168 

Peabody   *11 

single  service 165 

Staples   &   Pfeifer *10 

testing 271 

Burning  point   of  oil 136 

Bursting  pressure,   boiler 

plate 152 

Bursting  pressure,   boiler 

seam    154 

Bush    St.    Station,  G.W.P.Co.. 274 

Calculations,  boiler  test  data. 249 
Calibration,  thermometer  ....   33 
California   Accident   Commis- 
sion  311 

California  oils    134 

Calorific  value   (see  Heating 

value) 
Calorimeter — 

fuel   (see  Fuel  calorimeter) 
steam  (see  Steam  calorimeter) 
Carbon  dioxide   in  chimney 

*203,  204 

Carbon  monoxide  in  chimney. 205 
Centigrade   and   Fahrenheit. .   34 

Centigrade  and  Reamur 35 

Centrifuge,  electric *184 

Check  valves *118,  119 


Chemical  properties  of  oil 133 

Chemical    steam   calorimeter.   94 

Chimney 113 

Chimney  draft  pressure, 

measuring   *30 

Chimney  gas — 

analysis 112,  203,  248 

absorption    solutions    207 

by    weight    210,211,212 

CO  content   205 

CC-2  content   204 

CC-2  recorder 203 

check  on    205 

combustion  recorder *206 

data  from  Orsat  analysis.  .218 

hydrogen   content    208 

nitrogen   content    205 

Orsat  apparatus *210 

oxygen  content  204 

per  pound  of  fuel 222 

reading  gage   *205 

tabulation  suggested    214 

taking  samples   203 

tests  for  efficiency   275 

volume   to   weight 213 

Circulating  water  cycle.... *2,  9 
Circulating  water  pump.  .*2,  *48 
Circulation  of  water  in  boiler.  127 

Cleaning  boiler   145 

Coal,  powdered  299 

Coal  production    *298 

Color  of  flame,  temperature 

by   36 

Color  of  oils  133 

Column    of  mercury 24 

Combustion — 

air  required  for 214 

air  supplied  to  furnace 219 

air  supply,  actual  and  ideal. 225 
chimney  gas  per  Ib.  of  fuel. 222 

data 218 

incomplete,    heat   loss 260 

of  pound  of  oil 228 

operation,  recorder  for 206 

oxygen  required  for 216 

Commerce  and  Labor,  Dept. 

of 140 

Commercial  furnace 162 

Composite  law  of  gases 48 

Compression  of  boiler  plate..  151 

Condenser *2,    8 

Condenser  barometer *27 

Condenser  vacuum   *24 

Connecting   up   boiler   units..  143 

Construction  of  furnace 109 

Consumption  of  oil 131 

Control   of   furnace,    typical.  *276 

Controller,  master *274 

Conversion  of  pressures 27 

Cooling  boiler   145 

Crude  oil   (see  Fuel  oil) 
Cycle — 

circulating  water 9 

oil *2,     9 

steam   *2,     3 

Cylinder   oil,    keep   out  of 

boiler 144 

Damper,   furnace   *276 

Davy's  experiments   43 

Density  of  oils   134 

Density,  formula  for  gas 48 


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316 


FUEL  OIL  AND  STEAM  ENGINEERING 


Density  of  steam,  specific. ...   66 

Differential  draft  gage *241 

Distillation,    for   moisture 

determinations   186,  189 

Draft — 

gage 112 

gage,  differential   *241 

pressure  in  chimney,  meas- 
uring    *30 

regulating  devices 112 

tests 273 

Drum  and  tubes,  boiler 123 

Drum,    mud    121 

Dry  saturated  steam.58,  68,  81,  86 

Dry  vacuum  pump *2,     9 

Dulong's  formula  for  heating 
value   192 

East    India   petroleum 133 

Economizer *2,  6,  111 

Edgemoor  boiler    129 

Efficiency   of   boiler 264 

(see  Heat  balance) 

Efficiency  of  burners 270 

Efficiency,   tests  of  chimney 

gas    for    275 

Electric  steam  calorimeter. 97,  98 

Electric   thermometers    39 

Electric  centrifuge    184 

Emerson    fuel    calorimeter.  .*194 
Energy,  kinetic  and  potential.21 

Engine,   reciprocating   7 

Entropy — 

of  evaporation    71 

of  water 69 

temperature  diagram *69 

total  71 

Erie  City  boiler   129 

Evaporation   79 

entropy  of 71 

equivalent 79 

latent  heat   of... 55,  67,  104,  105 

standard  for  boilers   80 

Evaporative  tests   270 

(see  also  Tests) 

Expansion,  provision  for 120 

Expansion  pyrometer   39 

External  and  internal  work. .   68 
Externally   fired   boilers 123 

Fahrenheit — 

in  steam  tables 63 

reduction  to  Centigrade. ...   34 

reduction    to    Reamur 35 

Feed-water   heaters    *2,     5 

Feed  water,  injector  for 117 

Feed  water,  pump  for. .  *2,  5,  117 
Fire   tests,    Saybolt  equip- 
ment   *131 

Fire-tube  boiler  123 

Flame  color,  temperature  by.  36 

Flash  test  for  oil *131,  136 

Flow  of  steam  in  atomiza- 

tion 237 

Flue  gas  (see  Chimney  gas) 

Force,  defined   16 

Force,  pound  17 

Front  shot  burner.  170,  *172,  *174 
Fruitvale  Station,  S.  P.  Co. .   77 


Fuel  Calorimeter  193 

Atwater-Mahler    bomb. . . . *194 

Emerson *194 

Mahler  bomb  197 

Parr    *195,  *196,  196 

Fuel  oil — 

advantages  as  fuel 132 

calorific  value   134 

cycles *2,     9 

density  of  various  types...  134 
determination  of  heating 

value   191 

effect  of  heat 134 

feed,  log  sheet  for. . .  .250,  *251 
flash  test  and  burning  point.  136 

gravity  of  176 

measurement  and  analysis. 245 
moisture  (see  moisture  content) 

odor  and   color 133 

physical    and    chemical 

properties 133 

sampling 233 

specifications    for   pur- 
chase   133,  137 

study   310 

sulphur  and  gas  content. .  .137 

test  data 267 

viscosity 136 

weighing 229,  232 

(see  also  Petroleum) 

Fuels  defined  110 

Furnace *2,  157 

air  spaces  and  grate  bars.*160 

arrangement    *162,  270 

brickwork  and  air  spac- 

ings   *158 

'commercial 162 

construction,   efficient 109 

control   of    *276 

floor,  air  ducts  for *107 

former  type    *61 

gases,  path  of Ill 

interior 157 

marine,   brick  work *164 

operation 107,  110,  157 

regulation  of  air 163,  164 

single    burner    165 

Fusion,  latent  heat  of 54 

Gage — 

draft 112,  *218,  *241 

safety *119 

pressure — absolute  pressure  24 
recording  COa  in  chimney.  *205 

steam 23,    *23,   *29 

steam,  tester *20 

water  and  steam 119 

Galvanometer  for  delicate 

temperatures   *42 

Gas- 
analysis,  chimney   203 

chimney,   ingredients  of.  . .  .112 

composite  law  of 48 

defined 52 

density,  formula  for 48 

furnace,   path  of   Ill 

heat  loss  due  to 259 

in  oil 137 

natural   299 

to  compute   "R"    49 


Page  numbers  referring  to  illustrations  are  marked  by  an  asterisk  (*) 


INDEX 


317 


Goetz  attachment  for  water 
determination    *186 

Graphic  law  for  calorific 

value   *191 

Grate  bars — furnace *160 

Gravity — 

Baume  readings  and 178 

by  Westphal  balance 179 

commercial   balance  for...*180 

computations    179,  *181 

liquids  heavier  than  water.  177 
liquids   lighter   than    water.  177 

of  oils 176 

range  of 138 

Gt.    Western    Power    Station. 274 

Heat- 
absorbed  by  boiler.  . .  .255,  *256 

absorption,  law  of 116 

effect  on  oil 134 

in  steam  generation.  . .  .115,  245 

latent  of  evaporation 67 

mechanical  equivalent  for.  .    44 
of    evaporation,    formula.  .  .105 

of  liquid  66 

of  saturated  steam,   total..  103 

specific  of  steam *67 

specific  of  water.  . . '. *64 

temperature  diagrams *56 

transfer,   equivalent  for.  . .  .116 

transfer,    rate   of 117 

unit  (B.  t.  u.),  denned 45 

Heat  balance — 

boiler  efficiency   109,  255 

loss  by  boiler  absorption. .  .255 

loss   due  to  gases 259 

loss  due  to  hydrogen 258 

loss  due  to  incomplete  com- 
bustion    - 260 

loss  due  to  moisture 257 

loss    for   atomization.  .  .256,  261 
loss   in   evaporating   steam. 260 

summary   of   data 264 

total  heat  absorbed 255 

Heaters,  feed-water  *2,     5 

Heating  value — 

approximate   method    192 

Dulong's    formula    192 

graphic   law   for *191 

higher    and   lower 201 

of  fuel  oil 134 

range  of 138 

Heine  boiler 129 

Hemphel   apparatus  for  H  in 

chimney   208 

Henning's   formula   104 

Home-made  burner   ....169,  *170 

Horizontal  boilers 125,  *128 

Horsepower — 

boiler 72,  73,  *74,  83 

development    of   word 73 

mechanical   *74 

types  of   *74 

Hot-well   *2,     5 

Humidity,  hygrometer  for.  . .  .  *38 
Hydrogen,   heat  loss  due  to.. 258 

Hydrometers,    Baume    *176 

Hydrometer,    limitations    of..  178 
Hygrometer  for  humidity. ..  .*38 

Ice,  formation  of  53 

Illustrative  problems   279 


Immersion,  method  of 37 

Injector  for  feed   water 117 

Inside  mixer    166,  *167 

Inspection,  steamboat   140 

Inspection  tests    140 

Inspectors,  insurance 155 

Inspector's  outfit   *141 

Inspiration  Copper  Co.'s 

plant *272 

Interior  of  furnace *157 

Internal  and  external  work. .  .   68 

Internal  boiler  pressure *149 

Internally   fired  boilers 123 

Joint,  double  riveted  butt...*155 
Joint,  double  riveted  lap.*153,  156 
Joint,  single  riveted  lap....*151 
Joule's  equivalent,  defined.  .  45 

Keeler  boiler   129 

Kern   River  oil 134 

Kier,  discoverer  of  petroleum.  131 

Kilowatt    *74 

Kinetic  energy    21 

Knoblauch — specific  heat  of 
steam *67 

Laboratory  equipment  for 

testing  oil *135 

Latent  heat  of  evaporation. . 

55,  67,  104 

Latent  heat  of  fusion 54 

Latitude  and  altitude,  barom- 
eter corrections    31 

Laws,    fundamental    14 

Laws   of  thermodynamics....   43 

Le  Conte's  law   192 

Length,  fundamental  unit.  ...   16 

Liquid  fuels  classified   ;133 

Liquid,    heat    of 66 

Liquids,   defined   52 

Liquids  heavier  than  water, 

gravity  scale    177 

Liquids   lighter   than   water, 

gravity  scale   177 

Log  sheet  for  boiler  tests.... 

251,    *252,   *253 

Log  sheet  for  fuel  oil  feed.  . 

250,  *251 

Log  sheet  for  weighing  water 

249,    *250 

Long  Beach  Power  Plant..  .3,  *44 
Low  water  in  boiler 143 

Mahler  bomb  fuel  calori- 
meter   *197 

Manholes   120 

Marine   boilers    125,129 

Marine  furnace,  brickwork.  .  *164 

Marine    tankers    *302 

Marks  &  Davis  method *64 

Mass — fundamental   unit    16 

Measurer  of  water *234 

Measuring  tank  for  water. *4,*230 

Mechanical  atomizer 168,  169 

Mechanical  equivalent  of  heat  44 

Mechanical   horsepower    *74 

Mechanical  hp.   to  boiler  hp..   75 

Melting  alloys,  cup  for *37 

Melting  point  of  metals 37 

Mercurial  thermometers 38 

Mercury,   column  of 24 

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318 


FUEL  OIL  AND  STEAM  ENGINEERING 


Metals,  melting  point  of 37 

Meter,  steam  *236 

Mines,  U.   S.  Bureau  of 310 

Mixer   (see  Burner) 

Moisture  content 137,  184 

apparatus  involved  188 

approximate  method   186 

by  distillation   186,  189 

by  Goetz  attachment *186 

methods  of  determining. .  .184 
numerical  determination . .  .  189 
percentages  by  weight — 

error 90 

still  used  in  determination. *187 
Moisture  in  saturated  steam.   89 

Moisture,  rejection  for 139 

Moore,  C.  C.,  system 11 

Motion,  Newton's  laws  of.  ...   15 

Mud  drum 121 

Myriawatt *74,  76,  77 

Napier's  formula  237 

Natural  gas 299 

Naval  Fuel  Oil  Board,  U.  S.  .166 

Newton's  laws  of  motion 15 

Nipple,  sampling,  steam 

calorimeter  100 

Nitrogen  in  chimney  gas 205 

Non-return  and  check  valves.119 
Numerical  determination  of 

moisture 189 

Nussett's  law 116 

Oakland  Station,   P.  G.  &.  E.  .*47 

Odor  and  color  of  oil 133 

Oil  (see  Fuel  oil) 

Olefine  base,   petroleum 133 

Operation,  furnace   107 

Operation  of  boiler,  report  on.  277 
Orsat  analysis  (see  Chimney 
gas  analysis) 

Orsat    apparatus    *210 

Outside   mixer    168,  *168 

Overload  test 245 

Oxygen  in  chimney  gas 204 

Oxygen  required  for  combus- 
tion   216 

Pacific  Gas  &  Electric  Co...  3 
Paraffine  base,  petroleum. .  .  .133 

Parker  boiler *18,  127 

Parr  fuel  calorimeter — 

*195,  *196,  196 

correction 200 

operation   196 

precautions 198 

Peabody  atomizer  *11 

Pensky-Martens  tester 138 

Pet  cocks  for  water  level.  . .  .*119 
Petroleum — 

Appalachian  Range 133 

asphalt  base 133 

California 133 

commission 292 

comparative  uses *300 

comparison  with  coal *298 

conservation  of 297 

consumption  of 295 

discovery  of  131 

hydro-electric  substitution 

'for *307 

Middle  West 133 


oleflne  base 133 

paraff ine  base   133 

pipe    lines    *292 

production    of    *294 

recommendations 292 

refining  of  *297 

storage  depletion   295 

storage  of   295 

Texas 133 

the  remedy 301 

utilization 293 

(see  also  Fuel  oil) 
Physical  properties — Califor- 
nia   oils    134 

Physical  properties  of  oil.  . .  .133 
Platform  scales,  water  meas- 
urement   *93,  230 

Pop  safety  valve  *12l 

Potential  energy 21 

Pound  force   17 

Pound  of  oil,   combustion  of. 228 

Poundals 17 

Powdered   coal    299 

Power  plant,  modern 1 

Power,  work  and  19 

Pressure — 

above    atmosphere,    meas- 
urement of   *24 

absolute,  gage  24 

absolute  notation,  steam 

tables    63 

formula  for  conversion  of .  .   27 

in  atmospheres  64 

in  saturated  steam   103 

inches  of  water  and 26 

internal  boiler *149 

readings   247 

safe  working  boiler 134 

theory  of   23 

units,   confusion  in   26 

units,  relationship  of 26 

vacuum 25 

Pump,    supply    *2 

Power    Test    Committee, 

A.  S.  M.  E 243 

Pressure,   working,   rules  for.  140 

Problems,    illustrative    279 

Pump — 

boiler  test   *143 

circulating   water    *2,  *48 

dry  vacuum    *2,     9 

for  feed-water   *2,   5,   117 

for  storage  supply 4 

oil  feed   *2 

wet  vacuum    *2,     9 

Purchase   of  oil,    specifica- 
tions  for    131,  137 

Purifying   tank  for  water.  . .  .    *4 

Pyrometer *215 

expansion 39 

radiation 40 

Quality  of  steam 85 

Quick  steaming  test 246 

Radiation   pyrometer   40 

Railroad  Commission,   Cali- 
fornia   310 

Rating  boiler,  to  compute.  ...  78 

Rating,   builder's    77 

Rating — its  meaning 73 

Reamur   scale    35 


Page  numbers  referring  to  illustrations  are  marked  by  an  asterisk  (*) 


INDEX 


319 


Reciprocating  engine 7 

Reciprocating  units  at  Re- 

dondo *14 

Recorder  for  combustion.  . .  .  *206 

Redondo  Power  Plant 

3,  *4,  *6,  *14,  *48 

Regnault's  formula 103 

Regulator,  steam  to  burner.. *12 

Repairs,  under  pressure 144 

Return  tubular  boiler 123 

Riveted  joint,   boiler 151,  *153 

Riveted  section,  boiler  shell..  151 

Russian  petroleum    133 

Rust  boiler   139 

Safety,  factors  of 154 

Safety  gage *119 

Safety  valve   22,   121,   *121 

Sampling — 

nipple,  steam  calorimeter.  .100 

of  oil 233,  235 

Saturated  steam 

81,  85,  86,  89,  103 

Saybolt  equipment  for  tests. *131 

Scale,  absolute   48 

Scales,    platform    *83,  230 

Scales,   temperature    33,  *34 

Scotch  marine  boiler 125 

Sediment  in  boiler,   remove..  144 

Sellegries,  process  of  131 

Separating  calorimeter   ..*95.  98 

Separator *2,     7 

Shear  of  boiler  plate 150 

Shredded  Wheat  Plant *242 

Siphons  for  steam  gage *120 

Smoke-stack *2 

Solids,    denned    52 

Southern  California  Edison 

Company   3 

Specific  density  of  steam....   66 
Specific   gravity    (see   Gravity) 
Specific  heat  of  superheated 

steam *67 

Specific  heat  of  water *64 

Specific  volume  for  steam. 65,  105 
Specifications  for  purchase 

of  oil 131,  137 

Standard  Oil  Co.'s  chart 158 

Standardization  of  thermom- 
eters     41 

Standards,  U.  S.  Bureau  of.  .310 
Staples  &  Pfeifer  atomizer. . .  *10 
States  possible  to  all  bodies.  .  53 
Station  A,  P.  G.  &  E.  Co..  .3,  *122 

Station  C,  P.  G.  &  E.  Co 3,  *18 

Steam- 
boiler,  principles 115 

calorimeter  (see  Steam 
calorimeter) 

cycle *2,     3 

dry  saturated  68,  81,  86 

ducts,   Oakland  station *47 

engineering.  ..  .53,  102,  103,  163 

formation  of 55 

formulas 102,   103,  163 

gage    (see   Steam  gage) 
generation,  laws  of  heat...  115 
in   atomization    (see    Steam 

in  atomization) 
meter *236 


quality   of    85 

quantity  for  atomizing  oil..  171 

saturated 81,  85,  86,  89,  103 

specific  density  of 66 

specific  heat  of *67 

specific  volume  of  65 

superheated    (see    Superheated 

steam) 
tables  (see  Steam  tables) 

to  burner  regulator *12 

total  heat   of 58 

turbine   7,  *16 

turbine,   condenser  barom- 
eter for *27 

water  and   52 

wet   saturated    81,  85 

Steamboat  inspection  service.  140 

Steam  calorimeter 88,  93 

attachment *244 

barrel  or  tank 89 

chemical 94 

conclusions    on    100 

corrections  for   steam 99 

electric 97 

sampling  nipple   100 

separating *95,  98 

surface  condenser  tank  ....   91 

Thomas  electric   98 

throttling* *93,  94,  96,  *101 

Steam   Engineering — 

formulas 102,  103,  163 

fundamental  principle   53 

Steam  gage    23 

siphon  for  *120 

hand  adjuster  for *29 

interior  and   exterior *25 

tester  *20 

water  gages  and 119 

Steam  in  atomization 236 

calibration  of  orifice *239 

measurement *238 

tested 245 

Steam   tables    61,  62 

analysis   of    62 

data  deduced  57 

Fahrenheit  used 63 

pressure  absolute  notations  63 

typical  page  *63 

Still,  for  water  *187 

Stirling  boiler 128,  !:=174,  *175 

Stop  valves *118 

Storage   tank    *2,     3 

Storage  supply,  pumps  for. .  .  4 
Strength  of  boiler  shells.  147,  148 
Sulphur  and  gas  in  oil.  .  .137,  139 
Superheated  steam.  . .  .82,  *85,  86 

determination   of    89 

specific  volume  for 105 

tables   for    71 

temperature *88 

total  heat  of 87 

where   temperatures   taken.  *79 

Superheater *2,     7 

Supply  pump   *2 

Supply  water  source *2 

Surface  condenser  tank, 
steam  calorimeter  91 

Tables  for  steam 61 

Tabulation  of  test  data.. 249,  267 


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320 


FUEL  OIL  AND  STEAM  ENGINEERING 


Tank — 

for  measuring  water  and 

oil 230,  *231 

for  water  supply   *4 

for  weighing  oil   *229 

or  barrel  steam  calorimeter.  89 
steam    calorimeter,    surface 

condenser 91 

storage *2,     3 

Tankers,  marine *302 

Tea-kettle  and  boiler 107,108 

Temperature — 

by  flame  color 36 

by  galvanometer   *42 

entropy   diagram    *69 

Fahrenheit  in  steam  tables.  63 

heat  diagram *56 

measurement 32,  36 

measurement,  pyrometer  .*215 

of  saturated  steam 103 

readings   248 

scales 33,  *34 

superheated  steam   *88 

Test- 
committee  A.S.M.E.,  power.243 

data  for  boilers 241 

data,  tabulation   267 

evaporative 270 

flash  and  fire,  equipment.  .131 

inspection 140 

of  boiler  regulation 277. 

of  burners 271 

of  furnace  arrangement.  . .  .270 

of  furnace  draft 273 

of  oil,  equipment *136 

outfit   141 

pump,  portable   *143 

records  of  278 

specimen,  standard  form..*147 

thermometers 41 

(see  also  Boiler  tests) 

Tester,   Abel-Pensky   138 

Tester,  Pensky-Martens 138 

Tester,    steam   gage *20 

Thermo-couple  ..*30,  32,  *39,  *40 
Thermodynamics,  laws  of.  ...  43 
Thermodynamics,  first  law  of  45 

Thermometer — 

alcohol 38 

barometer  correction   *23 

calibration 33 

electrical 39 

for  superheat *85 

galvanometer    for   delicate 

temperatures *42 

mercurial 38 

standardization  and  testing.  41 

well  for  insertion *41 

Thirty  inch  vacuum 26,  38 

Thomas  electric  steam  calori- 
meter     98 

Thornycrof t   boiler   130 

Throttling  steam   calorimeter 

*93,  94,  96,  *101 

Time — fundamental  unit  ....  16 
Torpedo  boat  boiler 130 


Total  heat  of  steam.... 58,  68,  87 

Tubes,  boiler  drum  and 123 

Turbine *2,  7,  *16 

Units,  fundamental 16 

Units  of  power,  chart *74 

University  of  California 309 

Vacuum — 

condenser *24 

pressure • 25 

pump,   dry    *2,     9 

pump,  wet  *2,     9 

thirty  inch 26,  28 

Valve — 

check   or   non-return 119 

pet  cock *119 

pop  safety *121 

safety 22,  121 

stop,  check  or  blow-off.  . .  .*118 

Velocity  defined  16 

Vertical  boilers 125 

Viscosimeter *235 

Viscosity  of  oils  136 

Volume  of  steam,  specific.  ...   65 
Volume,   specific  for  super- 
heated steam 105 

Volumetric  method  of  water 
measurement 229 

Water— 

and  oil,  weighing 229 

and  steam 52 

cycle,   circulating    *2,     9 

determination  (see  Moisture 
content) 

entropy    of    69 

gage  and  steam  gages 119 

heat  loss  due  to  257 

in  boiler,  circulation  of 127 

inches  of  and  pressure 26 

measurement,   platform 

scales    *83,  230 

measurement,    volumetric 

method   229 

measurer 234 

pump,  circulating *2 

source,  supply *2 

specific  heat  of *64 

supply,  tank  for *4 

tube  boiler   123 

weighing  of    244,   249.,  *250 

Weighing — 

oil   *229,  232 

tank  in  boiler  test *231 

water  and  oil 229 

water,  log  sheet  for.  .  .249,  *250 
Well   for   thermometer   inser- 
tion  *41 

Westphal  balance   179 

Wet  saturated  steam 81,    85 

West  vacuum  pump *2,     ! 

Work  and  power 19 

Work,  external  and  internal..   68 
Working  pressure,  rules  for..  140 

Zero  scale,  absolute 47 


Page  numbers  referring  to  illustrations  are  marked  by  an  asterisk  (*) 


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